21939366 has 8 divisors (see below), whose sum is σ = 43878744. Its totient is φ = 7313120.

The previous prime is 21939361. The next prime is 21939383. The reversal of 21939366 is 66393912.

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

21939366 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21939361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1828275 + ... + 1828286.

It is an arithmetic number, because the mean of its divisors is an integer number (5484843).

Almost surely, 2^21939366 is an apocalyptic number.

21939366 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.

21939366 is a wasteful number, since it uses less digits than its factorization.

21939366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3656566.

The product of its digits is 52488, while the sum is 39.

The square root of 21939366 is about 4683.9476939863. The cubic root of 21939366 is about 279.9462737053.

The spelling of 21939366 in words is "twenty-one million, nine hundred thirty-nine thousand, three hundred sixty-six".