21660412 has 6 divisors (see below), whose sum is σ = 37905728. Its totient is φ = 10830204.

The previous prime is 21660409. The next prime is 21660421. The reversal of 21660412 is 21406612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2707548 + ... + 2707555.

Almost surely, 2^21660412 is an apocalyptic number.

It is an amenable number.

21660412 is a deficient number, since it is larger than the sum of its proper divisors (16245316).

21660412 is a wasteful number, since it uses less digits than its factorization.

21660412 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5415107 (or 5415105 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21660412 is about 4654.0747737869. The cubic root of 21660412 is about 278.7547250635.

The spelling of 21660412 in words is "twenty-one million, six hundred sixty thousand, four hundred twelve".