21523210531 has 2 divisors, whose sum is σ = 21523210532. Its totient is φ = 21523210530.

The previous prime is 21523210529. The next prime is 21523210567. The reversal of 21523210531 is 13501232512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21523210531 - 2¹ = 21523210529 is a prime.

It is a super-2 number, since 2×21523210531² (a number of 21 digits) contains 22 as substring.

Together with 21523210529, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 21523210496 and 21523210505.

It is not a weakly prime, because it can be changed into another prime (21523210591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10761605265 + 10761605266.

It is an arithmetic number, because the mean of its divisors is an integer number (10761605266).

Almost surely, 2^21523210531 is an apocalyptic number.

21523210531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21523210531 is an equidigital number, since it uses as much as digits as its factorization.

21523210531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1800, while the sum is 25.

The spelling of 21523210531 in words is "twenty-one billion, five hundred twenty-three million, two hundred ten thousand, five hundred thirty-one".