20856668858 has 16 divisors (see below), whose sum is σ = 33686746560. Its totient is φ = 9648547776.

The previous prime is 20856668851. The next prime is 20856668879. The reversal of 20856668858 is 85886665802.

It is a self number, because there is not a number n which added to its sum of digits gives 20856668858.

It is not an unprimeable number, because it can be changed into a prime (20856668851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5196566 + ... + 5200577.

It is an arithmetic number, because the mean of its divisors is an integer number (2105421660).

Almost surely, 2^20856668858 is an apocalyptic number.

20856668858 is a deficient number, since it is larger than the sum of its proper divisors (12830077702).

20856668858 is a wasteful number, since it uses less digits than its factorization.

20856668858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10397221.

The product of its (nonzero) digits is 44236800, while the sum is 62.

The spelling of 20856668858 in words is "twenty billion, eight hundred fifty-six million, six hundred sixty-eight thousand, eight hundred fifty-eight".