20578899857 has 4 divisors (see below), whose sum is σ = 21789423396. Its totient is φ = 19368376320.

The previous prime is 20578899773. The next prime is 20578899883. The reversal of 20578899857 is 75899887502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75899887502 = 2 ⋅37949943751.

It can be written as a sum of positive squares in 2 ways, for example, as 17167288576 + 3411611281 = 131024^2 + 58409^2 .

It is a cyclic number.

It is not a de Polignac number, because 20578899857 - 2²⁴ = 20562122641 is a prime.

It is a super-2 number, since 2×20578899857² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20578829857) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 605261744 + ... + 605261777.

It is an arithmetic number, because the mean of its divisors is an integer number (5447355849).

Almost surely, 2^20578899857 is an apocalyptic number.

It is an amenable number.

20578899857 is a deficient number, since it is larger than the sum of its proper divisors (1210523539).

20578899857 is a wasteful number, since it uses less digits than its factorization.

20578899857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1210523538.

The product of its (nonzero) digits is 101606400, while the sum is 68.

The spelling of 20578899857 in words is "twenty billion, five hundred seventy-eight million, eight hundred ninety-nine thousand, eight hundred fifty-seven".