21878413808 has 20 divisors (see below), whose sum is σ = 42673924200. Its totient is φ = 10865788224.

The previous prime is 21878413793. The next prime is 21878413841. The reversal of 21878413808 is 80831487812.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4586210 + ... + 4590977.

It is an arithmetic number, because the mean of its divisors is an integer number (2133696210).

Almost surely, 2^21878413808 is an apocalyptic number.

It is an amenable number.

21878413808 is a deficient number, since it is larger than the sum of its proper divisors (20795510392).

21878413808 is a wasteful number, since it uses less digits than its factorization.

21878413808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9177344 (or 9177338 counting only the distinct ones).

The product of its (nonzero) digits is 688128, while the sum is 50.

The spelling of 21878413808 in words is "twenty-one billion, eight hundred seventy-eight million, four hundred thirteen thousand, eight hundred eight".