21685446 has 24 divisors (see below), whose sum is σ = 48606480. Its totient is φ = 6979056.

The previous prime is 21685409. The next prime is 21685457. The reversal of 21685446 is 64458612.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21685446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20250 + ... + 21293.

It is an arithmetic number, because the mean of its divisors is an integer number (2025270).

Almost surely, 2^21685446 is an apocalyptic number.

21685446 is an abundant number, since it is smaller than the sum of its proper divisors (26921034).

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

21685446 is a wasteful number, since it uses less digits than its factorization.

21685446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41580 (or 41577 counting only the distinct ones).

The product of its digits is 46080, while the sum is 36.

The square root of 21685446 is about 4656.7634683329. The cubic root of 21685446 is about 278.8620738851.

The spelling of 21685446 in words is "twenty-one million, six hundred eighty-five thousand, four hundred forty-six".