21534121456 has 20 divisors (see below), whose sum is σ = 41785500904. Its totient is φ = 10750766400.

The previous prime is 21534121439. The next prime is 21534121579. The reversal of 21534121456 is 65412143512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1007490 + ... + 1028641.

Almost surely, 2^21534121456 is an apocalyptic number.

It is an amenable number.

21534121456 is a deficient number, since it is larger than the sum of its proper divisors (20251379448).

21534121456 is a wasteful number, since it uses less digits than its factorization.

21534121456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2036800 (or 2036794 counting only the distinct ones).

The product of its digits is 28800, while the sum is 34.

Adding to 21534121456 its reverse (65412143512), we get a palindrome (86946264968).

The spelling of 21534121456 in words is "twenty-one billion, five hundred thirty-four million, one hundred twenty-one thousand, four hundred fifty-six".