21682806 has 12 divisors (see below), whose sum is σ = 43388436. Its totient is φ = 7223800.

The previous prime is 21682757. The next prime is 21682823. The reversal of 21682806 is 60828612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10456 + ... + 12356.

It is an arithmetic number, because the mean of its divisors is an integer number (3615703).

Almost surely, 2^21682806 is an apocalyptic number.

21682806 is an abundant number, since it is smaller than the sum of its proper divisors (21705630).

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

21682806 is an frugal number, since it uses more digits than its factorization.

21682806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3807 (or 1906 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 21682806 is about 4656.4800010308. The cubic root of 21682806 is about 278.8507571437.

The spelling of 21682806 in words is "twenty-one million, six hundred eighty-two thousand, eight hundred six".