21936939 has 8 divisors (see below), whose sum is σ = 29686080. Its totient is φ = 14406216.

The previous prime is 21936931. The next prime is 21936961. The reversal of 21936939 is 93963912.

It is a happy number.

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

It is not a de Polignac number, because 21936939 - 2³ = 21936931 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21936939.

It is not an unprimeable number, because it can be changed into a prime (21936931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54369 + ... + 54770.

It is an arithmetic number, because the mean of its divisors is an integer number (3710760).

Almost surely, 2^21936939 is an apocalyptic number.

21936939 is a deficient number, since it is larger than the sum of its proper divisors (7749141).

21936939 is a wasteful number, since it uses less digits than its factorization.

21936939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109209.

The product of its digits is 78732, while the sum is 42.

The square root of 21936939 is about 4683.6886104864. The cubic root of 21936939 is about 279.9359504860.

The spelling of 21936939 in words is "twenty-one million, nine hundred thirty-six thousand, nine hundred thirty-nine".