21919313 has 16 divisors (see below), whose sum is σ = 24290112. Its totient is φ = 19656000.

The previous prime is 21919309. The next prime is 21919319. The reversal of 21919313 is 31391912.

It is not a de Polignac number, because 21919313 - 2² = 21919309 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21919319) 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 in 15 ways as a sum of consecutive naturals, for example, 103778 + ... + 103988.

It is an arithmetic number, because the mean of its divisors is an integer number (1518132).

Almost surely, 2^21919313 is an apocalyptic number.

It is an amenable number.

21919313 is a deficient number, since it is larger than the sum of its proper divisors (2370799).

21919313 is a wasteful number, since it uses less digits than its factorization.

21919313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 416.

The product of its digits is 1458, while the sum is 29.

The square root of 21919313 is about 4681.8065957491. The cubic root of 21919313 is about 279.8609556237.

The spelling of 21919313 in words is "twenty-one million, nine hundred nineteen thousand, three hundred thirteen".