21940806 has 8 divisors (see below), whose sum is σ = 43881624. Its totient is φ = 7313600.

The previous prime is 21940799. The next prime is 21940813. The reversal of 21940806 is 60804912.

It is an interprime number because it is at equal distance from previous prime (21940799) and next prime (21940813).

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

21940806 is an admirable number.

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, 1828395 + ... + 1828406.

It is an arithmetic number, because the mean of its divisors is an integer number (5485203).

Almost surely, 2^21940806 is an apocalyptic number.

21940806 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21940806 is a wasteful number, since it uses less digits than its factorization.

21940806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3656806.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 21940806 is about 4684.1014079544. The cubic root of 21940806 is about 279.9523983705.

The spelling of 21940806 in words is "twenty-one million, nine hundred forty thousand, eight hundred six".