21936293 has 2 divisors, whose sum is σ = 21936294. Its totient is φ = 21936292.

The previous prime is 21936253. The next prime is 21936323. The reversal of 21936293 is 39263912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21548164 + 388129 = 4642^2 + 623^2 .

It is a cyclic number.

It is not a de Polignac number, because 21936293 - 2⁸ = 21936037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21936253) 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 as a sum of consecutive naturals, namely, 10968146 + 10968147.

It is an arithmetic number, because the mean of its divisors is an integer number (10968147).

Almost surely, 2^21936293 is an apocalyptic number.

21936293 is the 2504-th centered heptagonal number.

It is an amenable number.

21936293 is a deficient number, since it is larger than the sum of its proper divisors (1).

21936293 is an equidigital number, since it uses as much as digits as its factorization.

21936293 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 35.

The square root of 21936293 is about 4683.6196472387. The cubic root of 21936293 is about 279.9332026034.

The spelling of 21936293 in words is "twenty-one million, nine hundred thirty-six thousand, two hundred ninety-three".