20215631 has 8 divisors (see below), whose sum is σ = 20715264. Its totient is φ = 19720480.

The previous prime is 20215621. The next prime is 20215661. The reversal of 20215631 is 13651202.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20215631 is a prime.

It is a super-2 number, since 2×20215631² = 817343473456322, which 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 (20215621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9125 + ... + 11121.

It is an arithmetic number, because the mean of its divisors is an integer number (2589408).

Almost surely, 2^20215631 is an apocalyptic number.

20215631 is a deficient number, since it is larger than the sum of its proper divisors (499633).

20215631 is a wasteful number, since it uses less digits than its factorization.

20215631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2241.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 20215631 is about 4496.1796005053. The cubic root of 20215631 is about 272.4137976081.

Adding to 20215631 its reverse (13651202), we get a palindrome (33866833).

The spelling of 20215631 in words is "twenty million, two hundred fifteen thousand, six hundred thirty-one".