21581080878 has 48 divisors (see below), whose sum is σ = 52851640320. Its totient is φ = 5841494064.

The previous prime is 21581080853. The next prime is 21581080883. The reversal of 21581080878 is 87808018512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1926126 + ... + 1937297.

It is an arithmetic number, because the mean of its divisors is an integer number (1101075840).

Almost surely, 2^21581080878 is an apocalyptic number.

21581080878 is an abundant number, since it is smaller than the sum of its proper divisors (31270559442).

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

21581080878 is a wasteful number, since it uses less digits than its factorization.

21581080878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3863461 (or 3863454 counting only the distinct ones).

The product of its (nonzero) digits is 286720, while the sum is 48.

The spelling of 21581080878 in words is "twenty-one billion, five hundred eighty-one million, eighty thousand, eight hundred seventy-eight".