20857755321 has 36 divisors (see below), whose sum is σ = 33917500708. Its totient is φ = 12277438272.

The previous prime is 20857755319. The next prime is 20857755341. The reversal of 20857755321 is 12355775802.

20857755321 is a `hidden beast` number, since 2 + 0 + 8 + 5 + 77 + 553 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 9872409600 + 10985345721 = 99360^2 + 104811^2 .

It is not a de Polignac number, because 20857755321 - 2¹ = 20857755319 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20857755341) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 106606 + ... + 230391.

Almost surely, 2^20857755321 is an apocalyptic number.

It is an amenable number.

20857755321 is a deficient number, since it is larger than the sum of its proper divisors (13059745387).

20857755321 is a wasteful number, since it uses less digits than its factorization.

20857755321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 337062 (or 337036 counting only the distinct ones).

The product of its (nonzero) digits is 588000, while the sum is 45.

The spelling of 20857755321 in words is "twenty billion, eight hundred fifty-seven million, seven hundred fifty-five thousand, three hundred twenty-one".