21596939 has 16 divisors (see below), whose sum is σ = 27982080. Its totient is φ = 16187040.

The previous prime is 21596921. The next prime is 21596951. The reversal of 21596939 is 93969512.

It is a cyclic number.

It is not a de Polignac number, because 21596939 - 2¹² = 21592843 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21596939.

It is not an unprimeable number, because it can be changed into a prime (21596959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4517 + ... + 7974.

It is an arithmetic number, because the mean of its divisors is an integer number (1748880).

Almost surely, 2^21596939 is an apocalyptic number.

21596939 is a deficient number, since it is larger than the sum of its proper divisors (6385141).

21596939 is a wasteful number, since it uses less digits than its factorization.

21596939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12530.

The product of its digits is 131220, while the sum is 44.

The square root of 21596939 is about 4647.2506926139. The cubic root of 21596939 is about 278.4821739292.

The spelling of 21596939 in words is "twenty-one million, five hundred ninety-six thousand, nine hundred thirty-nine".