20187631 has 4 divisors (see below), whose sum is σ = 20215264. Its totient is φ = 20160000.

The previous prime is 20187599. The next prime is 20187637. The reversal of 20187631 is 13678102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13678102 = 2 ⋅6839051.

It is a cyclic number.

It is not a de Polignac number, because 20187631 - 2⁵ = 20187599 is a prime.

It is a super-2 number, since 2×20187631² = 815080890784322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20187631.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20187637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12690 + ... + 14191.

It is an arithmetic number, because the mean of its divisors is an integer number (5053816).

Almost surely, 2^20187631 is an apocalyptic number.

20187631 is a deficient number, since it is larger than the sum of its proper divisors (27633).

20187631 is an equidigital number, since it uses as much as digits as its factorization.

20187631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27632.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 20187631 is about 4493.0647669492. The cubic root of 20187631 is about 272.2879690580.

The spelling of 20187631 in words is "twenty million, one hundred eighty-seven thousand, six hundred thirty-one".