21684430 has 16 divisors (see below), whose sum is σ = 39332304. Its totient is φ = 8607040.

The previous prime is 21684413. The next prime is 21684461. The reversal of 21684430 is 3448612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6967 + ... + 9586.

It is an arithmetic number, because the mean of its divisors is an integer number (2458269).

Almost surely, 2^21684430 is an apocalyptic number.

21684430 is a deficient number, since it is larger than the sum of its proper divisors (17647874).

21684430 is a wasteful number, since it uses less digits than its factorization.

21684430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16691.

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 21684430 is about 4656.6543784138. The cubic root of 21684430 is about 278.8577187630.

The spelling of 21684430 in words is "twenty-one million, six hundred eighty-four thousand, four hundred thirty".