21878566040 has 32 divisors (see below), whose sum is σ = 49295304000. Its totient is φ = 8739243264.

The previous prime is 21878566033. The next prime is 21878566043. The reversal of 21878566040 is 4066587812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21878566043) 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, 351605 + ... + 409124.

It is an arithmetic number, because the mean of its divisors is an integer number (1540478250).

Almost surely, 2^21878566040 is an apocalyptic number.

21878566040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21878566040 is an abundant number, since it is smaller than the sum of its proper divisors (27416737960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21878566040 is a wasteful number, since it uses less digits than its factorization.

21878566040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 761459 (or 761455 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 47.

The spelling of 21878566040 in words is "twenty-one billion, eight hundred seventy-eight million, five hundred sixty-six thousand, forty".