21743631 has 48 divisors (see below), whose sum is σ = 39137280. Its totient is φ = 11327040.

The previous prime is 21743627. The next prime is 21743639. The reversal of 21743631 is 13634712.

21743631 is a `hidden beast` number, since 21 + 7 + 4 + 3 + 631 = 666.

It is not a de Polignac number, because 21743631 - 2² = 21743627 is a prime.

It is a super-2 number, since 2×21743631² = 945570978128322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21743595 and 21743604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21743639) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 113746 + ... + 113936.

It is an arithmetic number, because the mean of its divisors is an integer number (815360).

Almost surely, 2^21743631 is an apocalyptic number.

21743631 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21743631 is a deficient number, since it is larger than the sum of its proper divisors (17393649).

21743631 is a wasteful number, since it uses less digits than its factorization.

21743631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356 (or 353 counting only the distinct ones).

The product of its digits is 3024, while the sum is 27.

The square root of 21743631 is about 4663.0066480759. The cubic root of 21743631 is about 279.1112594378. Note that the first 3 decimals are identical.

The spelling of 21743631 in words is "twenty-one million, seven hundred forty-three thousand, six hundred thirty-one".