21140631 has 6 divisors (see below), whose sum is σ = 30536480. Its totient is φ = 14093748.

The previous prime is 21140621. The next prime is 21140633. The reversal of 21140631 is 13604112.

21140631 = 599² + 600² + ... + 652².

It is a happy number.

21140631 is a `hidden beast` number, since 21 + 14 + 0 + 631 = 666.

It is not a de Polignac number, because 21140631 - 2⁵ = 21140599 is a prime.

It is a super-2 number, since 2×21140631² = 893852558156322, 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 (21140633) 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, 1174471 + ... + 1174488.

Almost surely, 2^21140631 is an apocalyptic number.

21140631 is a deficient number, since it is larger than the sum of its proper divisors (9395849).

21140631 is a wasteful number, since it uses less digits than its factorization.

21140631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2348965 (or 2348962 counting only the distinct ones).

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

The square root of 21140631 is about 4597.8941919100. The cubic root of 21140631 is about 276.5069055541.

Adding to 21140631 its reverse (13604112), we get a palindrome (34744743).

The spelling of 21140631 in words is "twenty-one million, one hundred forty thousand, six hundred thirty-one".