30691185721 has 27 divisors (see below), whose sum is σ = 37018441551. Its totient is φ = 25370170224.

The previous prime is 30691185713. The next prime is 30691185727. The reversal of 30691185721 is 12758119603.

The square root of 30691185721 is 175189.

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

It can be written as a sum of positive squares in only one way, i.e., 16093713321 + 14597472400 = 126861^2 + 120820^2 .

It is not a de Polignac number, because 30691185721 - 2³ = 30691185713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (30691185727) 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 26 ways as a sum of consecutive naturals, for example, 35562936 + ... + 35563798.

Almost surely, 2^30691185721 is an apocalyptic number.

30691185721 is the 175189-th square number.

30691185721 is the 87595-th centered octagonal number.

It is an amenable number.

30691185721 is a deficient number, since it is larger than the sum of its proper divisors (6327255830).

30691185721 is an frugal number, since it uses more digits than its factorization.

30691185721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1798 (or 899 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 43.

The spelling of 30691185721 in words is "thirty billion, six hundred ninety-one million, one hundred eighty-five thousand, seven hundred twenty-one".