21365933 has 2 divisors, whose sum is σ = 21365934. Its totient is φ = 21365932.

The previous prime is 21365917. The next prime is 21365941. The reversal of 21365933 is 33956312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18550249 + 2815684 = 4307^2 + 1678^2 .

It is a cyclic number.

It is not a de Polignac number, because 21365933 - 2⁴ = 21365917 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21365933.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21365033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10682966 + 10682967.

It is an arithmetic number, because the mean of its divisors is an integer number (10682967).

Almost surely, 2^21365933 is an apocalyptic number.

It is an amenable number.

21365933 is a deficient number, since it is larger than the sum of its proper divisors (1).

21365933 is an equidigital number, since it uses as much as digits as its factorization.

21365933 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14580, while the sum is 32.

The square root of 21365933 is about 4622.3298238010. The cubic root of 21365933 is about 277.4857087573.

The spelling of 21365933 in words is "twenty-one million, three hundred sixty-five thousand, nine hundred thirty-three".