21919345 has 32 divisors (see below), whose sum is σ = 31882752. Its totient is φ = 14141952.

The previous prime is 21919321. The next prime is 21919349. The reversal of 21919345 is 54391912.

It is a cyclic number.

It is not a de Polignac number, because 21919345 - 2¹⁵ = 21886577 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21919345.

It is not an unprimeable number, because it can be changed into a prime (21919349) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58579 + ... + 58951.

It is an arithmetic number, because the mean of its divisors is an integer number (996336).

Almost surely, 2^21919345 is an apocalyptic number.

It is an amenable number.

21919345 is a deficient number, since it is larger than the sum of its proper divisors (9963407).

21919345 is a wasteful number, since it uses less digits than its factorization.

21919345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 481.

The product of its digits is 9720, while the sum is 34.

The square root of 21919345 is about 4681.8100132321. The cubic root of 21919345 is about 279.8610918132.

The spelling of 21919345 in words is "twenty-one million, nine hundred nineteen thousand, three hundred forty-five".