21199499 has 2 divisors, whose sum is σ = 21199500. Its totient is φ = 21199498.

The previous prime is 21199489. The next prime is 21199531. The reversal of 21199499 is 99499112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21199499 - 2¹² = 21195403 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21199489) 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, 10599749 + 10599750.

It is an arithmetic number, because the mean of its divisors is an integer number (10599750).

Almost surely, 2^21199499 is an apocalyptic number.

21199499 is a deficient number, since it is larger than the sum of its proper divisors (1).

21199499 is an equidigital number, since it uses as much as digits as its factorization.

21199499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52488, while the sum is 44.

The square root of 21199499 is about 4604.2913678437. The cubic root of 21199499 is about 276.7633205307.

The spelling of 21199499 in words is "twenty-one million, one hundred ninety-nine thousand, four hundred ninety-nine".