21684486 has 16 divisors (see below), whose sum is σ = 45920304. Its totient is φ = 6802944.

The previous prime is 21684461. The next prime is 21684499. The reversal of 21684486 is 68448612.

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, 106195 + ... + 106398.

It is an arithmetic number, because the mean of its divisors is an integer number (2870019).

Almost surely, 2^21684486 is an apocalyptic number.

21684486 is an abundant number, since it is smaller than the sum of its proper divisors (24235818).

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

21684486 is a wasteful number, since it uses less digits than its factorization.

21684486 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212615.

The product of its digits is 73728, while the sum is 39.

The square root of 21684486 is about 4656.6603913105. The cubic root of 21684486 is about 278.8579588126.

The spelling of 21684486 in words is "twenty-one million, six hundred eighty-four thousand, four hundred eighty-six".