21607902557 has 2 divisors, whose sum is σ = 21607902558. Its totient is φ = 21607902556.

The previous prime is 21607902553. The next prime is 21607902593. The reversal of 21607902557 is 75520970612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17478426436 + 4129476121 = 132206^2 + 64261^2 .

It is a cyclic number.

It is not a de Polignac number, because 21607902557 - 2² = 21607902553 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21607902553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10803951278 + 10803951279.

It is an arithmetic number, because the mean of its divisors is an integer number (10803951279).

Almost surely, 2^21607902557 is an apocalyptic number.

It is an amenable number.

21607902557 is a deficient number, since it is larger than the sum of its proper divisors (1).

21607902557 is an equidigital number, since it uses as much as digits as its factorization.

21607902557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 264600, while the sum is 44.

The spelling of 21607902557 in words is "twenty-one billion, six hundred seven million, nine hundred two thousand, five hundred fifty-seven".