821796889 has 9 divisors (see below), whose sum is σ = 832571103. Its totient is φ = 811161432.

The previous prime is 821796863. The next prime is 821796893. The reversal of 821796889 is 988697128.

The square root of 821796889 is 28667.

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., 572788489 + 249008400 = 23933^2 + 15780^2 .

It is not a de Polignac number, because 821796889 - 2⁹ = 821796377 is a prime.

It is not an unprimeable number, because it can be changed into a prime (821796089) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3124572 + ... + 3124834.

Almost surely, 2^821796889 is an apocalyptic number.

821796889 is the 28667-th square number.

821796889 is the 14334-th centered octagonal number.

It is an amenable number.

821796889 is a deficient number, since it is larger than the sum of its proper divisors (10774214).

821796889 is an frugal number, since it uses more digits than its factorization.

821796889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 744 (or 372 counting only the distinct ones).

The product of its digits is 3483648, while the sum is 58.

The cubic root of 821796889 is about 936.6733506923.

It can be divided in two parts, 82 and 1796889, that added together give a palindrome (1796971).

The spelling of 821796889 in words is "eight hundred twenty-one million, seven hundred ninety-six thousand, eight hundred eighty-nine".