20916531631 has 4 divisors (see below), whose sum is σ = 20917081912. Its totient is φ = 20915981352.

The previous prime is 20916531593. The next prime is 20916531641. The reversal of 20916531631 is 13613561902.

It is a happy number.

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 20916531631 - 2¹¹ = 20916529583 is a prime.

It is a super-2 number, since 2×20916531631² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20916531641) 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, 213525 + ... + 295678.

It is an arithmetic number, because the mean of its divisors is an integer number (5229270478).

Almost surely, 2^20916531631 is an apocalyptic number.

20916531631 is a deficient number, since it is larger than the sum of its proper divisors (550281).

20916531631 is an equidigital number, since it uses as much as digits as its factorization.

20916531631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 550280.

The product of its (nonzero) digits is 29160, while the sum is 37.

The spelling of 20916531631 in words is "twenty billion, nine hundred sixteen million, five hundred thirty-one thousand, six hundred thirty-one".