21631746 has 8 divisors (see below), whose sum is σ = 43263504. Its totient is φ = 7210580.

The previous prime is 21631739. The next prime is 21631777. The reversal of 21631746 is 64713612.

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

21631746 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1802640 + ... + 1802651.

It is an arithmetic number, because the mean of its divisors is an integer number (5407938).

Almost surely, 2^21631746 is an apocalyptic number.

21631746 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21631746 is a wasteful number, since it uses less digits than its factorization.

21631746 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3605296.

The product of its digits is 6048, while the sum is 30.

The square root of 21631746 is about 4650.9940872893. The cubic root of 21631746 is about 278.6317001549.

The spelling of 21631746 in words is "twenty-one million, six hundred thirty-one thousand, seven hundred forty-six".