20507356857 has 16 divisors (see below), whose sum is σ = 29525427008. Its totient is φ = 12586069440.

The previous prime is 20507356843. The next prime is 20507356889. The reversal of 20507356857 is 75865370502.

It is not a de Polignac number, because 20507356857 - 2⁸ = 20507356601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20507356897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 690319 + ... + 719412.

It is an arithmetic number, because the mean of its divisors is an integer number (1845339188).

Almost surely, 2^20507356857 is an apocalyptic number.

It is an amenable number.

20507356857 is a deficient number, since it is larger than the sum of its proper divisors (9018070151).

20507356857 is a wasteful number, since it uses less digits than its factorization.

20507356857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1410120.

The product of its (nonzero) digits is 1764000, while the sum is 48.

The spelling of 20507356857 in words is "twenty billion, five hundred seven million, three hundred fifty-six thousand, eight hundred fifty-seven".