21620933 has 2 divisors, whose sum is σ = 21620934. Its totient is φ = 21620932.

The previous prime is 21620927. The next prime is 21620953. The reversal of 21620933 is 33902612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17156164 + 4464769 = 4142^2 + 2113^2 .

It is a cyclic number.

It is not a de Polignac number, because 21620933 - 2⁶ = 21620869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21620903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810466 + 10810467.

It is an arithmetic number, because the mean of its divisors is an integer number (10810467).

Almost surely, 2^21620933 is an apocalyptic number.

It is an amenable number.

21620933 is a deficient number, since it is larger than the sum of its proper divisors (1).

21620933 is an equidigital number, since it uses as much as digits as its factorization.

21620933 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 26.

The square root of 21620933 is about 4649.8315023235. The cubic root of 21620933 is about 278.5852661358.

The spelling of 21620933 in words is "twenty-one million, six hundred twenty thousand, nine hundred thirty-three".