21916619 has 4 divisors (see below), whose sum is σ = 21944520. Its totient is φ = 21888720.

The previous prime is 21916607. The next prime is 21916651. The reversal of 21916619 is 91661912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21916619 is a prime.

It is a super-2 number, since 2×21916619² = 960676376782322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21916669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12737 + ... + 14354.

It is an arithmetic number, because the mean of its divisors is an integer number (5486130).

Almost surely, 2^21916619 is an apocalyptic number.

21916619 is a deficient number, since it is larger than the sum of its proper divisors (27901).

21916619 is an equidigital number, since it uses as much as digits as its factorization.

21916619 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27900.

The product of its digits is 5832, while the sum is 35.

The square root of 21916619 is about 4681.5188774585. The cubic root of 21916619 is about 279.8494896879.

The spelling of 21916619 in words is "twenty-one million, nine hundred sixteen thousand, six hundred nineteen".