21878413858 has 24 divisors (see below), whose sum is σ = 38428444224. Its totient is φ = 9314361000.

The previous prime is 21878413841. The next prime is 21878413913. The reversal of 21878413858 is 85831487812.

It is a Smith number, since the sum of its digits (55) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21878413799 and 21878413808.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 724438 + ... + 754033.

It is an arithmetic number, because the mean of its divisors is an integer number (1601185176).

Almost surely, 2^21878413858 is an apocalyptic number.

21878413858 is a deficient number, since it is larger than the sum of its proper divisors (16550030366).

21878413858 is a wasteful number, since it uses less digits than its factorization.

21878413858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1478638 (or 1478631 counting only the distinct ones).

The product of its digits is 3440640, while the sum is 55.

The spelling of 21878413858 in words is "twenty-one billion, eight hundred seventy-eight million, four hundred thirteen thousand, eight hundred fifty-eight".