21938997 has 8 divisors (see below), whose sum is σ = 29282656. Its totient is φ = 14610672.

The previous prime is 21938971. The next prime is 21939007. The reversal of 21938997 is 79983912.

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

It is not a de Polignac number, because 21938997 - 2²² = 17744693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21938947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78 + ... + 6624.

It is an arithmetic number, because the mean of its divisors is an integer number (3660332).

Almost surely, 2^21938997 is an apocalyptic number.

It is an amenable number.

21938997 is a deficient number, since it is larger than the sum of its proper divisors (7343659).

21938997 is a wasteful number, since it uses less digits than its factorization.

21938997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7667.

The product of its digits is 244944, while the sum is 48.

The square root of 21938997 is about 4683.9083039701. The cubic root of 21938997 is about 279.9447042167.

The spelling of 21938997 in words is "twenty-one million, nine hundred thirty-eight thousand, nine hundred ninety-seven".