21222332531 has 4 divisors (see below), whose sum is σ = 21715875192. Its totient is φ = 20728789872.

The previous prime is 21222332503. The next prime is 21222332567. The reversal of 21222332531 is 13523322212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21222332531 is a prime.

It is a super-2 number, since 2×21222332531² (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 21222332531.

It is not an unprimeable number, because it can be changed into a prime (21222532531) 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, 246771266 + ... + 246771351.

It is an arithmetic number, because the mean of its divisors is an integer number (5428968798).

Almost surely, 2^21222332531 is an apocalyptic number.

21222332531 is a deficient number, since it is larger than the sum of its proper divisors (493542661).

21222332531 is an equidigital number, since it uses as much as digits as its factorization.

21222332531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493542660.

The product of its digits is 4320, while the sum is 26.

Adding to 21222332531 its reverse (13523322212), we get a palindrome (34745654743).

The spelling of 21222332531 in words is "twenty-one billion, two hundred twenty-two million, three hundred thirty-two thousand, five hundred thirty-one".