21279030778 has 24 divisors (see below), whose sum is σ = 33076096092. Its totient is φ = 10266746112.

The previous prime is 21279030769. The next prime is 21279030821. The reversal of 21279030778 is 87703097212.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 11904337449 + 9374693329 = 109107^2 + 96823^2 .

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, 4904226 + ... + 4908562.

Almost surely, 2^21279030778 is an apocalyptic number.

21279030778 is a deficient number, since it is larger than the sum of its proper divisors (11797065314).

21279030778 is a wasteful number, since it uses less digits than its factorization.

21279030778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7314 (or 7285 counting only the distinct ones).

The product of its (nonzero) digits is 296352, while the sum is 46.

The spelling of 21279030778 in words is "twenty-one billion, two hundred seventy-nine million, thirty thousand, seven hundred seventy-eight".