21190631 has 16 divisors (see below), whose sum is σ = 26611200. Its totient is φ = 16392480.

The previous prime is 21190627. The next prime is 21190661. The reversal of 21190631 is 13609112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21190631 - 2² = 21190627 is a prime.

It is a super-2 number, since 2×21190631² = 898085684356322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21190597 and 21190606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21190621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10550 + ... + 12396.

It is an arithmetic number, because the mean of its divisors is an integer number (1663200).

Almost surely, 2^21190631 is an apocalyptic number.

21190631 is a deficient number, since it is larger than the sum of its proper divisors (5420569).

21190631 is a wasteful number, since it uses less digits than its factorization.

21190631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2014.

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 21190631 is about 4603.3282524712. The cubic root of 21190631 is about 276.7247240300.

Adding to 21190631 its reverse (13609112), we get a palindrome (34799743).

The spelling of 21190631 in words is "twenty-one million, one hundred ninety thousand, six hundred thirty-one".