21173514312878 has 64 divisors (see below), whose sum is σ = 34929217986048. Its totient is φ = 9582717173760.

The previous prime is 21173514312877. The next prime is 21173514312913. The reversal of 21173514312878 is 87821341537112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21173514312877) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 198690026 + ... + 198796562.

It is an arithmetic number, because the mean of its divisors is an integer number (545769031032).

Almost surely, 2^{21173514312878} is an apocalyptic number.

21173514312878 is a deficient number, since it is larger than the sum of its proper divisors (13755703673170).

21173514312878 is a wasteful number, since it uses less digits than its factorization.

21173514312878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107757.

The product of its digits is 2257920, while the sum is 53.

The spelling of 21173514312878 in words is "twenty-one trillion, one hundred seventy-three billion, five hundred fourteen million, three hundred twelve thousand, eight hundred seventy-eight".