21933257 has 4 divisors (see below), whose sum is σ = 21946320. Its totient is φ = 21920196.

The previous prime is 21933253. The next prime is 21933259. The reversal of 21933257 is 75233912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21933257 - 2² = 21933253 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21933253) 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 3 ways as a sum of consecutive naturals, for example, 3563 + ... + 7520.

It is an arithmetic number, because the mean of its divisors is an integer number (5486580).

Almost surely, 2^21933257 is an apocalyptic number.

It is an amenable number.

21933257 is a deficient number, since it is larger than the sum of its proper divisors (13063).

21933257 is a wasteful number, since it uses less digits than its factorization.

21933257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13062.

The product of its digits is 11340, while the sum is 32.

The square root of 21933257 is about 4683.2955277240. The cubic root of 21933257 is about 279.9202876833.

The spelling of 21933257 in words is "twenty-one million, nine hundred thirty-three thousand, two hundred fifty-seven".