21233533257 has 18 divisors (see below), whose sum is σ = 31400542602. Its totient is φ = 13826475936.

The previous prime is 21233533253. The next prime is 21233533271. The reversal of 21233533257 is 75233533212.

It can be written as a sum of positive squares in only one way, i.e., 13962730896 + 7270802361 = 118164^2 + 85269^2 .

It is not a de Polignac number, because 21233533257 - 2² = 21233533253 is a prime.

It is a super-2 number, since 2×21233533257² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21233533253) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 621348 + ... + 654629.

It is an arithmetic number, because the mean of its divisors is an integer number (1744474589).

Almost surely, 2^21233533257 is an apocalyptic number.

It is an amenable number.

21233533257 is a deficient number, since it is larger than the sum of its proper divisors (10167009345).

21233533257 is a wasteful number, since it uses less digits than its factorization.

21233533257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1276069 (or 1276023 counting only the distinct ones).

The product of its digits is 113400, while the sum is 36.

The spelling of 21233533257 in words is "twenty-one billion, two hundred thirty-three million, five hundred thirty-three thousand, two hundred fifty-seven".