21523250531 has 4 divisors (see below), whose sum is σ = 21678094200. Its totient is φ = 21368406864.

The previous prime is 21523250513. The next prime is 21523250543. The reversal of 21523250531 is 13505232512.

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 21523250531 - 2⁶ = 21523250467 is a prime.

It is a super-2 number, since 2×21523250531² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21523250494 and 21523250503.

It is not an unprimeable number, because it can be changed into a prime (21523210531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77421626 + ... + 77421903.

It is an arithmetic number, because the mean of its divisors is an integer number (5419523550).

Almost surely, 2^21523250531 is an apocalyptic number.

21523250531 is a deficient number, since it is larger than the sum of its proper divisors (154843669).

21523250531 is a wasteful number, since it uses less digits than its factorization.

21523250531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154843668.

The product of its (nonzero) digits is 9000, while the sum is 29.

The spelling of 21523250531 in words is "twenty-one billion, five hundred twenty-three million, two hundred fifty thousand, five hundred thirty-one".