21385933 has 4 divisors (see below), whose sum is σ = 21493600. Its totient is φ = 21278268.

The previous prime is 21385891. The next prime is 21385937. The reversal of 21385933 is 33958312.

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 21385933 - 2¹⁷ = 21254861 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 (21385937) 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, 53535 + ... + 53932.

It is an arithmetic number, because the mean of its divisors is an integer number (5373400).

Almost surely, 2^21385933 is an apocalyptic number.

It is an amenable number.

21385933 is a deficient number, since it is larger than the sum of its proper divisors (107667).

21385933 is a wasteful number, since it uses less digits than its factorization.

21385933 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107666.

The product of its digits is 19440, while the sum is 34.

The square root of 21385933 is about 4624.4927289380. The cubic root of 21385933 is about 277.5722637330.

The spelling of 21385933 in words is "twenty-one million, three hundred eighty-five thousand, nine hundred thirty-three".