21531432311 has 4 divisors (see below), whose sum is σ = 22113362952. Its totient is φ = 20949501672.

The previous prime is 21531432289. The next prime is 21531432319. The reversal of 21531432311 is 11323413512.

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 21531432311 - 2¹⁰ = 21531431287 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531432319) 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, 290965265 + ... + 290965338.

It is an arithmetic number, because the mean of its divisors is an integer number (5528340738).

Almost surely, 2^21531432311 is an apocalyptic number.

21531432311 is a deficient number, since it is larger than the sum of its proper divisors (581930641).

21531432311 is an equidigital number, since it uses as much as digits as its factorization.

21531432311 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 581930640.

The product of its digits is 2160, while the sum is 26.

Adding to 21531432311 its reverse (11323413512), we get a palindrome (32854845823).

The spelling of 21531432311 in words is "twenty-one billion, five hundred thirty-one million, four hundred thirty-two thousand, three hundred eleven".