21057804278 has 16 divisors (see below), whose sum is σ = 37343890080. Its totient is φ = 8713574016.

The previous prime is 21057804269. The next prime is 21057804281. The reversal of 21057804278 is 87240875012.

It is a super-2 number, since 2×21057804278² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25932851 + ... + 25933662.

It is an arithmetic number, because the mean of its divisors is an integer number (2333993130).

Almost surely, 2^21057804278 is an apocalyptic number.

21057804278 is a deficient number, since it is larger than the sum of its proper divisors (16286085802).

21057804278 is a wasteful number, since it uses less digits than its factorization.

21057804278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51866551.

The product of its (nonzero) digits is 250880, while the sum is 44.

The spelling of 21057804278 in words is "twenty-one billion, fifty-seven million, eight hundred four thousand, two hundred seventy-eight".