21622609 has 4 divisors (see below), whose sum is σ = 21977140. Its totient is φ = 21268080.

The previous prime is 21622607. The next prime is 21622613. The reversal of 21622609 is 90622612.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3814209 + 17808400 = 1953^2 + 4220^2 .

It is a cyclic number.

It is not a de Polignac number, because 21622609 - 2¹ = 21622607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21622607) 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, 177174 + ... + 177295.

It is an arithmetic number, because the mean of its divisors is an integer number (5494285).

Almost surely, 2^21622609 is an apocalyptic number.

It is an amenable number.

21622609 is a deficient number, since it is larger than the sum of its proper divisors (354531).

21622609 is an equidigital number, since it uses as much as digits as its factorization.

21622609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354530.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 21622609 is about 4650.0117204153. The cubic root of 21622609 is about 278.5924643581.

The spelling of 21622609 in words is "twenty-one million, six hundred twenty-two thousand, six hundred nine".