21979254067 has 16 divisors (see below), whose sum is σ = 22215660768. Its totient is φ = 21744702720.

The previous prime is 21979254013. The next prime is 21979254103. The reversal of 21979254067 is 76045297912.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21979254067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21979251067) 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, 40626817 + ... + 40627357.

It is an arithmetic number, because the mean of its divisors is an integer number (1388478798).

Almost surely, 2^21979254067 is an apocalyptic number.

21979254067 is a deficient number, since it is larger than the sum of its proper divisors (236406701).

21979254067 is a wasteful number, since it uses less digits than its factorization.

21979254067 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1590.

The product of its (nonzero) digits is 1905120, while the sum is 52.

The spelling of 21979254067 in words is "twenty-one billion, nine hundred seventy-nine million, two hundred fifty-four thousand, sixty-seven".