21278619879 has 16 divisors (see below), whose sum is σ = 30980275200. Its totient is φ = 12883818560.

The previous prime is 21278619863. The next prime is 21278619881. The reversal of 21278619879 is 97891687212.

It is a cyclic number.

It is not a de Polignac number, because 21278619879 - 2⁴ = 21278619863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21278619179) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 272727 + ... + 341960.

It is an arithmetic number, because the mean of its divisors is an integer number (1936267200).

Almost surely, 2^21278619879 is an apocalyptic number.

21278619879 is a deficient number, since it is larger than the sum of its proper divisors (9701655321).

21278619879 is a wasteful number, since it uses less digits than its factorization.

21278619879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 615750.

The product of its digits is 6096384, while the sum is 60.

The spelling of 21278619879 in words is "twenty-one billion, two hundred seventy-eight million, six hundred nineteen thousand, eight hundred seventy-nine".