21297535131 has 4 divisors (see below), whose sum is σ = 28396713512. Its totient is φ = 14198356752.

The previous prime is 21297535033. The next prime is 21297535159. The reversal of 21297535131 is 13153579212.

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

It is not a de Polignac number, because 21297535131 - 2⁹ = 21297534619 is a prime.

It is a super-2 number, since 2×21297535131² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21297535131.

It is not an unprimeable number, because it can be changed into a prime (21297535031) 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, 3549589186 + ... + 3549589191.

It is an arithmetic number, because the mean of its divisors is an integer number (7099178378).

Almost surely, 2^21297535131 is an apocalyptic number.

21297535131 is a deficient number, since it is larger than the sum of its proper divisors (7099178381).

21297535131 is an equidigital number, since it uses as much as digits as its factorization.

21297535131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7099178380.

The product of its digits is 56700, while the sum is 39.

The spelling of 21297535131 in words is "twenty-one billion, two hundred ninety-seven million, five hundred thirty-five thousand, one hundred thirty-one".