21064486878 has 24 divisors (see below), whose sum is σ = 45813266928. Its totient is φ = 6994796352.

The previous prime is 21064486847. The next prime is 21064486889. The reversal of 21064486878 is 87868446012.

21064486878 is a `hidden beast` number, since 21 + 0 + 64 + 486 + 87 + 8 = 666.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

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, 2220075 + ... + 2229542.

It is an arithmetic number, because the mean of its divisors is an integer number (1908886122).

Almost surely, 2^21064486878 is an apocalyptic number.

21064486878 is an abundant number, since it is smaller than the sum of its proper divisors (24748780050).

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

21064486878 is a wasteful number, since it uses less digits than its factorization.

21064486878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4449888 (or 4449885 counting only the distinct ones).

The product of its (nonzero) digits is 4128768, while the sum is 54.

The spelling of 21064486878 in words is "twenty-one billion, sixty-four million, four hundred eighty-six thousand, eight hundred seventy-eight".