20995009 has 4 divisors (see below), whose sum is σ = 23994304. Its totient is φ = 17995716.

The previous prime is 20994989. The next prime is 20995031. The reversal of 20995009 is 90059902.

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 not a de Polignac number, because 20995009 - 2¹³ = 20986817 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20995069) 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, 1499637 + ... + 1499650.

It is an arithmetic number, because the mean of its divisors is an integer number (5998576).

Almost surely, 2^20995009 is an apocalyptic number.

It is an amenable number.

20995009 is a deficient number, since it is larger than the sum of its proper divisors (2999295).

20995009 is an equidigital number, since it uses as much as digits as its factorization.

20995009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2999294.

The product of its (nonzero) digits is 7290, while the sum is 34.

The square root of 20995009 is about 4582.0310998508. The cubic root of 20995009 is about 275.8705590959.

The spelling of 20995009 in words is "twenty million, nine hundred ninety-five thousand, nine".