2639861 has 4 divisors (see below), whose sum is σ = 3016992. Its totient is φ = 2262732.

The previous prime is 2639827. The next prime is 2639863. The reversal of 2639861 is 1689362.

2639861 is digitally balanced in base 8, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 2639861 - 2¹⁴ = 2623477 is a prime.

It is a d-powerful number, because it can be written as 2²¹ + 6⁴ + 3⁷ + 9⁶ + 8 + 6⁵ + 1 .

It is a Duffinian number.

2639861 is strictly pandigital in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2639863) 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, 188555 + ... + 188568.

It is an arithmetic number, because the mean of its divisors is an integer number (754248).

2^2639861 is an apocalyptic number.

It is an amenable number.

2639861 is a deficient number, since it is larger than the sum of its proper divisors (377131).

2639861 is an equidigital number, since it uses as much as digits as its factorization.

2639861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 377130.

The product of its digits is 15552, while the sum is 35.

The square root of 2639861 is about 1624.7649060710. The cubic root of 2639861 is about 138.2060389293.

The spelling of 2639861 in words is "two million, six hundred thirty-nine thousand, eight hundred sixty-one".