21261156454 has 16 divisors (see below), whose sum is σ = 34932124800. Its totient is φ = 9660241024.

The previous prime is 21261156419. The next prime is 21261156481. The reversal of 21261156454 is 45465116212.

It is a super-2 number, since 2×21261156454² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10780534 + ... + 10782505.

It is an arithmetic number, because the mean of its divisors is an integer number (2183257800).

Almost surely, 2^21261156454 is an apocalyptic number.

21261156454 is a deficient number, since it is larger than the sum of its proper divisors (13670968346).

21261156454 is a wasteful number, since it uses less digits than its factorization.

21261156454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21563087.

The product of its digits is 57600, while the sum is 37.

The spelling of 21261156454 in words is "twenty-one billion, two hundred sixty-one million, one hundred fifty-six thousand, four hundred fifty-four".