21535499 has 2 divisors, whose sum is σ = 21535500. Its totient is φ = 21535498.

The previous prime is 21535489. The next prime is 21535513. The reversal of 21535499 is 99453512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21535499 - 2²⁰ = 20486923 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21535489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10767749 + 10767750.

It is an arithmetic number, because the mean of its divisors is an integer number (10767750).

Almost surely, 2^21535499 is an apocalyptic number.

21535499 is a deficient number, since it is larger than the sum of its proper divisors (1).

21535499 is an equidigital number, since it uses as much as digits as its factorization.

21535499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48600, while the sum is 38.

The square root of 21535499 is about 4640.6356245670. The cubic root of 21535499 is about 278.2178433293.

The spelling of 21535499 in words is "twenty-one million, five hundred thirty-five thousand, four hundred ninety-nine".