21616899 has 8 divisors (see below), whose sum is σ = 28856592. Its totient is φ = 14394240.

The previous prime is 21616891. The next prime is 21616909. The reversal of 21616899 is 99861612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21616899 - 2³ = 21616891 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21616899.

It is not an unprimeable number, because it can be changed into a prime (21616891) 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 in 7 ways as a sum of consecutive naturals, for example, 922 + ... + 6639.

It is an arithmetic number, because the mean of its divisors is an integer number (3607074).

Almost surely, 2^21616899 is an apocalyptic number.

21616899 is a deficient number, since it is larger than the sum of its proper divisors (7239693).

21616899 is an equidigital number, since it uses as much as digits as its factorization.

21616899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8517.

The product of its digits is 46656, while the sum is 42.

The square root of 21616899 is about 4649.3977029288. The cubic root of 21616899 is about 278.5679390565.

The spelling of 21616899 in words is "twenty-one million, six hundred sixteen thousand, eight hundred ninety-nine".