21812806 has 8 divisors (see below), whose sum is σ = 33025320. Its totient is φ = 10804368.

The previous prime is 21812789. The next prime is 21812821. The reversal of 21812806 is 60821812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50751 + ... + 51178.

It is an arithmetic number, because the mean of its divisors is an integer number (4128165).

Almost surely, 2^21812806 is an apocalyptic number.

21812806 is a deficient number, since it is larger than the sum of its proper divisors (11212514).

21812806 is a wasteful number, since it uses less digits than its factorization.

21812806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102038.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 21812806 is about 4670.4181825614. The cubic root of 21812806 is about 279.4069334914.

The spelling of 21812806 in words is "twenty-one million, eight hundred twelve thousand, eight hundred six".