7899865 has 8 divisors (see below), whose sum is σ = 9521928. Its totient is φ = 6291840.

The previous prime is 7899863. The next prime is 7899869. The reversal of 7899865 is 5689987.

It can be written as a sum of positive squares in 4 ways, for example, as 132496 + 7767369 = 364^2 + 2787^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 7899865 - 2¹ = 7899863 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7899863) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2226 + ... + 4555.

It is an arithmetic number, because the mean of its divisors is an integer number (1190241).

Almost surely, 2^7899865 is an apocalyptic number.

It is an amenable number.

7899865 is a deficient number, since it is larger than the sum of its proper divisors (1622063).

7899865 is a wasteful number, since it uses less digits than its factorization.

7899865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7019.

The product of its digits is 1088640, while the sum is 52.

The square root of 7899865 is about 2810.6698489862. The cubic root of 7899865 is about 199.1620356488.

It can be divided in two parts, 789 and 9865, that multiplied together give a triangular number (7783485 = T₃₉₄₅).

The spelling of 7899865 in words is "seven million, eight hundred ninety-nine thousand, eight hundred sixty-five".