2556664 has 32 divisors (see below), whose sum is σ = 5540400. Its totient is φ = 1093120.

The previous prime is 2556661. The next prime is 2556683. The reversal of 2556664 is 4666552.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2556661) 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, 642 + ... + 2350.

2^2556664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2556664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2770200).

2556664 is an abundant number, since it is smaller than the sum of its proper divisors (2983736).

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

2556664 is a wasteful number, since it uses less digits than its factorization.

2556664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1743 (or 1739 counting only the distinct ones).

The product of its digits is 43200, while the sum is 34.

The square root of 2556664 is about 1598.9571601516. The cubic root of 2556664 is about 136.7386282400.

The spelling of 2556664 in words is "two million, five hundred fifty-six thousand, six hundred sixty-four".