20557594637 has 2 divisors, whose sum is σ = 20557594638. Its totient is φ = 20557594636.

The previous prime is 20557594621. The next prime is 20557594667. The reversal of 20557594637 is 73649575502.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10606734121 + 9950860516 = 102989^2 + 99754^2 .

It is a cyclic number.

It is not a de Polignac number, because 20557594637 - 2⁴ = 20557594621 is a prime.

It is a super-2 number, since 2×20557594637² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20557594667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278797318 + 10278797319.

It is an arithmetic number, because the mean of its divisors is an integer number (10278797319).

Almost surely, 2^20557594637 is an apocalyptic number.

It is an amenable number.

20557594637 is a deficient number, since it is larger than the sum of its proper divisors (1).

20557594637 is an equidigital number, since it uses as much as digits as its factorization.

20557594637 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7938000, while the sum is 53.

The spelling of 20557594637 in words is "twenty billion, five hundred fifty-seven million, five hundred ninety-four thousand, six hundred thirty-seven".