2639664 has 60 divisors (see below), whose sum is σ = 7718256. Its totient is φ = 840576.

The previous prime is 2639639. The next prime is 2639669. The reversal of 2639664 is 4669362.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a zygodrome in base 3.

It is not an unprimeable number, because it can be changed into a prime (2639669) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2914 + ... + 3710.

2^2639664 is an apocalyptic number.

2639664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2639664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3859128).

2639664 is an abundant number, since it is smaller than the sum of its proper divisors (5078592).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2639664 is a wasteful number, since it uses less digits than its factorization.

2639664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 834 (or 825 counting only the distinct ones).

The product of its digits is 46656, while the sum is 36.

The square root of 2639664 is about 1624.7042807847. The cubic root of 2639664 is about 138.2026009620.

The spelling of 2639664 in words is "two million, six hundred thirty-nine thousand, six hundred sixty-four".