7864561 has 4 divisors (see below), whose sum is σ = 7870324. Its totient is φ = 7858800.

The previous prime is 7864501. The next prime is 7864573. The reversal of 7864561 is 1654687.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1654687 = 31 ⋅53377.

It can be written as a sum of positive squares in 2 ways, for example, as 4326400 + 3538161 = 2080^2 + 1881^2 .

It is a cyclic number.

It is not a de Polignac number, because 7864561 - 2⁷ = 7864433 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7864561.

It is not an unprimeable number, because it can be changed into a prime (7864501) 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, 451 + ... + 3991.

It is an arithmetic number, because the mean of its divisors is an integer number (1967581).

Almost surely, 2^7864561 is an apocalyptic number.

It is an amenable number.

7864561 is a deficient number, since it is larger than the sum of its proper divisors (5763).

7864561 is a wasteful number, since it uses less digits than its factorization.

7864561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5762.

The product of its digits is 40320, while the sum is 37.

The square root of 7864561 is about 2804.3824632172. The cubic root of 7864561 is about 198.8649117270.

The spelling of 7864561 in words is "seven million, eight hundred sixty-four thousand, five hundred sixty-one".