20964209 has 12 divisors (see below), whose sum is σ = 24908544. Its totient is φ = 17585064.

The previous prime is 20964197. The next prime is 20964221. The reversal of 20964209 is 90246902.

It is an interprime number because it is at equal distance from previous prime (20964197) and next prime (20964221).

It is not a de Polignac number, because 20964209 - 2¹² = 20960113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20964269) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2249 + ... + 6854.

It is an arithmetic number, because the mean of its divisors is an integer number (2075712).

Almost surely, 2^20964209 is an apocalyptic number.

It is an amenable number.

20964209 is a deficient number, since it is larger than the sum of its proper divisors (3944335).

20964209 is an equidigital number, since it uses as much as digits as its factorization.

20964209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9164 (or 9157 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 20964209 is about 4578.6689113759. The cubic root of 20964209 is about 275.7355909614.

The spelling of 20964209 in words is "twenty million, nine hundred sixty-four thousand, two hundred nine".