21352507531 has 2 divisors, whose sum is σ = 21352507532. Its totient is φ = 21352507530.

The previous prime is 21352507529. The next prime is 21352507543. The reversal of 21352507531 is 13570525312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21352507531 - 2¹ = 21352507529 is a prime.

It is a super-3 number, since 3×21352507531³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

Together with 21352507529, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21352507031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10676253765 + 10676253766.

It is an arithmetic number, because the mean of its divisors is an integer number (10676253766).

Almost surely, 2^21352507531 is an apocalyptic number.

21352507531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21352507531 is an equidigital number, since it uses as much as digits as its factorization.

21352507531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31500, while the sum is 34.

The spelling of 21352507531 in words is "twenty-one billion, three hundred fifty-two million, five hundred seven thousand, five hundred thirty-one".