2639857 has 6 divisors (see below), whose sum is σ = 2901794. Its totient is φ = 2399760.

The previous prime is 2639827. The next prime is 2639863. The reversal of 2639857 is 7589362.

2639857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 2405601 + 234256 = 1551^2 + 484^2 .

It is a de Polignac number, because none of the positive numbers 2^k-2639857 is a prime.

It is a Duffinian number.

2639857 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (2639827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10788 + ... + 11029.

2^2639857 is an apocalyptic number.

It is an amenable number.

2639857 is a deficient number, since it is larger than the sum of its proper divisors (261937).

2639857 is a wasteful number, since it uses less digits than its factorization.

2639857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21839 (or 21828 counting only the distinct ones).

The product of its digits is 90720, while the sum is 40.

The square root of 2639857 is about 1624.7636751232. The cubic root of 2639857 is about 138.2059691246.

The spelling of 2639857 in words is "two million, six hundred thirty-nine thousand, eight hundred fifty-seven".