2640569 has 4 divisors (see below), whose sum is σ = 2646900. Its totient is φ = 2634240.

The previous prime is 2640551. The next prime is 2640571. The reversal of 2640569 is 9650462.

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 1926544 + 714025 = 1388^2 + 845^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2640569 is a prime.

It is a super-2 number, since 2×2640569² = 13945209287522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (2640509) 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, 2492 + ... + 3389.

It is an arithmetic number, because the mean of its divisors is an integer number (661725).

2^2640569 is an apocalyptic number.

It is an amenable number.

2640569 is a deficient number, since it is larger than the sum of its proper divisors (6331).

2640569 is an equidigital number, since it uses as much as digits as its factorization.

2640569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6330.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 2640569 is about 1624.9827691394. The cubic root of 2640569 is about 138.2183932577.

The spelling of 2640569 in words is "two million, six hundred forty thousand, five hundred sixty-nine".