21822913 has 4 divisors (see below), whose sum is σ = 24940480. Its totient is φ = 18705348.

The previous prime is 21822907. The next prime is 21822923. The reversal of 21822913 is 31922812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21822913 is a prime.

It is the 4672-nd Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21822923) by changing a digit.

It is a nontrivial repunit in base 4671.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1558773 + ... + 1558786.

It is an arithmetic number, because the mean of its divisors is an integer number (6235120).

Almost surely, 2^21822913 is an apocalyptic number.

It is an amenable number.

21822913 is a deficient number, since it is larger than the sum of its proper divisors (3117567).

21822913 is an equidigital number, since it uses as much as digits as its factorization.

21822913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3117566.

The product of its digits is 1728, while the sum is 28.

The square root of 21822913 is about 4671.5000802740. The cubic root of 21822913 is about 279.4500813839.

The spelling of 21822913 in words is "twenty-one million, eight hundred twenty-two thousand, nine hundred thirteen".