21909059 has 4 divisors (see below), whose sum is σ = 22418616. Its totient is φ = 21399504.

The previous prime is 21909029. The next prime is 21909077. The reversal of 21909059 is 95090912.

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

It is a cyclic number.

It is not a de Polignac number, because 21909059 - 2¹² = 21904963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21909029) 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, 254714 + ... + 254799.

It is an arithmetic number, because the mean of its divisors is an integer number (5604654).

Almost surely, 2^21909059 is an apocalyptic number.

21909059 is a deficient number, since it is larger than the sum of its proper divisors (509557).

21909059 is an equidigital number, since it uses as much as digits as its factorization.

21909059 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509556.

The product of its (nonzero) digits is 7290, while the sum is 35.

The square root of 21909059 is about 4680.7113775579. The cubic root of 21909059 is about 279.8173085464.

The spelling of 21909059 in words is "twenty-one million, nine hundred nine thousand, fifty-nine".