21853399 has 2 divisors, whose sum is σ = 21853400. Its totient is φ = 21853398.

The previous prime is 21853393. The next prime is 21853487. The reversal of 21853399 is 99335812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21853399 - 2¹¹ = 21851351 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21853393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10926699 + 10926700.

It is an arithmetic number, because the mean of its divisors is an integer number (10926700).

Almost surely, 2^21853399 is an apocalyptic number.

21853399 is a deficient number, since it is larger than the sum of its proper divisors (1).

21853399 is an equidigital number, since it uses as much as digits as its factorization.

21853399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 58320, while the sum is 40.

The square root of 21853399 is about 4674.7619190714. The cubic root of 21853399 is about 279.5801488223.

The spelling of 21853399 in words is "twenty-one million, eight hundred fifty-three thousand, three hundred ninety-nine".