21631051 has 8 divisors (see below), whose sum is σ = 23925104. Its totient is φ = 19427040.

The previous prime is 21631039. The next prime is 21631061. The reversal of 21631051 is 15013612.

21631051 = 195² + 196² + ... + 416².

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

It is a cyclic number.

It is not a de Polignac number, because 21631051 - 2⁷ = 21630923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21631061) 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, 22005 + ... + 22966.

It is an arithmetic number, because the mean of its divisors is an integer number (2990638).

Almost surely, 2^21631051 is an apocalyptic number.

21631051 is a deficient number, since it is larger than the sum of its proper divisors (2294053).

21631051 is a wasteful number, since it uses less digits than its factorization.

21631051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45021.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 21631051 is about 4650.9193714791. The cubic root of 21631051 is about 278.6287160977.

Adding to 21631051 its reverse (15013612), we get a palindrome (36644663).

The spelling of 21631051 in words is "twenty-one million, six hundred thirty-one thousand, fifty-one".