20531257231 has 4 divisors (see below), whose sum is σ = 20537062200. Its totient is φ = 20525452264.

The previous prime is 20531257169. The next prime is 20531257247. The reversal of 20531257231 is 13275213502.

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 20531257231 - 2³³ = 11941322639 is a prime.

It is a super-2 number, since 2×20531257231² (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 = 20531257193 and 20531257202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20531257031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2897176 + ... + 2904253.

It is an arithmetic number, because the mean of its divisors is an integer number (5134265550).

Almost surely, 2^20531257231 is an apocalyptic number.

20531257231 is a deficient number, since it is larger than the sum of its proper divisors (5804969).

20531257231 is an equidigital number, since it uses as much as digits as its factorization.

20531257231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5804968.

The product of its (nonzero) digits is 12600, while the sum is 31.

The spelling of 20531257231 in words is "twenty billion, five hundred thirty-one million, two hundred fifty-seven thousand, two hundred thirty-one".