21631694 has 8 divisors (see below), whose sum is σ = 37082928. Its totient is φ = 9270720.

The previous prime is 21631691. The next prime is 21631697. The reversal of 21631694 is 49613612.

It is an interprime number because it is at equal distance from previous prime (21631691) and next prime (21631697).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21631694.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21631691) 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 3 ways as a sum of consecutive naturals, for example, 772547 + ... + 772574.

It is an arithmetic number, because the mean of its divisors is an integer number (4635366).

Almost surely, 2^21631694 is an apocalyptic number.

21631694 is a deficient number, since it is larger than the sum of its proper divisors (15451234).

21631694 is a wasteful number, since it uses less digits than its factorization.

21631694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1545130.

The product of its digits is 7776, while the sum is 32.

The square root of 21631694 is about 4650.9884970832. The cubic root of 21631694 is about 278.6314768896.

The spelling of 21631694 in words is "twenty-one million, six hundred thirty-one thousand, six hundred ninety-four".