21151525451431 has 4 divisors (see below), whose sum is σ = 21151557034552. Its totient is φ = 21151493868312.

The previous prime is 21151525451401. The next prime is 21151525451447. The reversal of 21151525451431 is 13415452515112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21151525451431 - 2²⁷ = 21151391233703 is a prime.

It is a super-2 number, since 2×21151525451431² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21151525451401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14764740 + ... + 16133833.

It is an arithmetic number, because the mean of its divisors is an integer number (5287889258638).

Almost surely, 2^{21151525451431} is an apocalyptic number.

21151525451431 is a deficient number, since it is larger than the sum of its proper divisors (31583121).

21151525451431 is an equidigital number, since it uses as much as digits as its factorization.

21151525451431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31583120.

The product of its digits is 120000, while the sum is 40.

Adding to 21151525451431 its reverse (13415452515112), we get a palindrome (34566977966543).

The spelling of 21151525451431 in words is "twenty-one trillion, one hundred fifty-one billion, five hundred twenty-five million, four hundred fifty-one thousand, four hundred thirty-one".