21319499 has 2 divisors, whose sum is σ = 21319500. Its totient is φ = 21319498.

The previous prime is 21319489. The next prime is 21319523. The reversal of 21319499 is 99491312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21319499 - 2⁴ = 21319483 is a prime.

It is a super-2 number, since 2×21319499² = 909042075222002, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21319489) 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, 10659749 + 10659750.

It is an arithmetic number, because the mean of its divisors is an integer number (10659750).

Almost surely, 2^21319499 is an apocalyptic number.

21319499 is a deficient number, since it is larger than the sum of its proper divisors (1).

21319499 is an equidigital number, since it uses as much as digits as its factorization.

21319499 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 38.

The square root of 21319499 is about 4617.3043001301. The cubic root of 21319499 is about 277.2845455828.

The spelling of 21319499 in words is "twenty-one million, three hundred nineteen thousand, four hundred ninety-nine".