21913299 has 24 divisors (see below), whose sum is σ = 33078240. Its totient is φ = 13961472.

The previous prime is 21913291. The next prime is 21913321. The reversal of 21913299 is 99231912.

It is a happy number.

It is not a de Polignac number, because 21913299 - 2³ = 21913291 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21913291) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29122 + ... + 29864.

It is an arithmetic number, because the mean of its divisors is an integer number (1378260).

Almost surely, 2^21913299 is an apocalyptic number.

21913299 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21913299 is a deficient number, since it is larger than the sum of its proper divisors (11164941).

21913299 is a wasteful number, since it uses less digits than its factorization.

21913299 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 891 (or 888 counting only the distinct ones).

The product of its digits is 8748, while the sum is 36.

The square root of 21913299 is about 4681.1642782539. The cubic root of 21913299 is about 279.8353581404.

The spelling of 21913299 in words is "twenty-one million, nine hundred thirteen thousand, two hundred ninety-nine".