21122631 has 6 divisors (see below), whose sum is σ = 30510480. Its totient is φ = 14081748.

The previous prime is 21122611. The next prime is 21122641. The reversal of 21122631 is 13622112.

21122631 is a `hidden beast` number, since 2 + 11 + 22 + 631 = 666.

It is not a de Polignac number, because 21122631 - 2¹³ = 21114439 is a prime.

It is a super-2 number, since 2×21122631² = 892331080724322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1173471 + ... + 1173488.

It is an arithmetic number, because the mean of its divisors is an integer number (5085080).

Almost surely, 2^21122631 is an apocalyptic number.

21122631 is a deficient number, since it is larger than the sum of its proper divisors (9387849).

21122631 is a wasteful number, since it uses less digits than its factorization.

21122631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2346965 (or 2346962 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 21122631 is about 4595.9363572617. The cubic root of 21122631 is about 276.4284068321.

Adding to 21122631 its reverse (13622112), we get a palindrome (34744743).

The spelling of 21122631 in words is "twenty-one million, one hundred twenty-two thousand, six hundred thirty-one".