21256627278 has 32 divisors (see below), whose sum is σ = 44439512832. Its totient is φ = 6765580800.

The previous prime is 21256627253. The next prime is 21256627279. The reversal of 21256627278 is 87272665212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21256627279) 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, 56083 + ... + 213678.

It is an arithmetic number, because the mean of its divisors is an integer number (1388734776).

Almost surely, 2^21256627278 is an apocalyptic number.

21256627278 is an abundant number, since it is smaller than the sum of its proper divisors (23182885554).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21256627278 is a wasteful number, since it uses less digits than its factorization.

21256627278 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 270360.

The product of its digits is 1128960, while the sum is 48.

The spelling of 21256627278 in words is "twenty-one billion, two hundred fifty-six million, six hundred twenty-seven thousand, two hundred seventy-eight".