830721050721 has 21 divisors (see below), whose sum is σ = 1245548706051. Its totient is φ = 553797627912.

The previous prime is 830721050713. The next prime is 830721050779. The reversal of 830721050721 is 127050127038.

The square root of 830721050721 is 911439.

It is a perfect power (a square), and thus also a powerful number.

830721050721 is a `hidden beast` number, since 83 + 0 + 72 + 1 + 0 + 507 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 523401606225 + 307319444496 = 723465^2 + 554364^2 .

It is not a de Polignac number, because 830721050721 - 2³ = 830721050713 is a prime.

It is a super-2 number, since 2×830721050721² (a number of 25 digits) contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (830721050921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 24591975 + ... + 24625731.

Almost surely, 2^830721050721 is an apocalyptic number.

830721050721 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

830721050721 is the 911439-th square number.

830721050721 is the 455720-th centered octagonal number.

It is an amenable number.

830721050721 is a deficient number, since it is larger than the sum of its proper divisors (414827655330).

830721050721 is an frugal number, since it uses more digits than its factorization.

830721050721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67532 (or 33760 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

Multiplying 830721050721 by its sum of digits (36), we get a square (29905957825956 = 5468634²).

Adding to 830721050721 its reverse (127050127038), we get a palindrome (957771177759).

The spelling of 830721050721 in words is "eight hundred thirty billion, seven hundred twenty-one million, fifty thousand, seven hundred twenty-one".