21621271263555 has 16 divisors (see below), whose sum is σ = 34626395164320. Its totient is φ = 11520557626368.

The previous prime is 21621271263541. The next prime is 21621271263587. The reversal of 21621271263555 is 55536217212612.

It is not a de Polignac number, because 21621271263555 - 2¹⁴ = 21621271247171 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 674173902 + ... + 674205971.

It is an arithmetic number, because the mean of its divisors is an integer number (2164149697770).

Almost surely, 2^{21621271263555} is an apocalyptic number.

21621271263555 is a deficient number, since it is larger than the sum of its proper divisors (13005123900765).

21621271263555 is a wasteful number, since it uses less digits than its factorization.

21621271263555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1348380950.

The product of its digits is 1512000, while the sum is 48.

The spelling of 21621271263555 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred seventy-one million, two hundred sixty-three thousand, five hundred fifty-five".