2500661 has 4 divisors (see below), whose sum is σ = 2519052. Its totient is φ = 2482272.

The previous prime is 2500651. The next prime is 2500669. The reversal of 2500661 is 1660052.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 498436 + 2002225 = 706^2 + 1415^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2500661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2500669) 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, 8990 + ... + 9263.

It is an arithmetic number, because the mean of its divisors is an integer number (629763).

2^2500661 is an apocalyptic number.

It is an amenable number.

2500661 is a deficient number, since it is larger than the sum of its proper divisors (18391).

2500661 is a wasteful number, since it uses less digits than its factorization.

2500661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18390.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 2500661 is about 1581.3478428227. The cubic root of 2500661 is about 135.7328413093.

The spelling of 2500661 in words is "two million, five hundred thousand, six hundred sixty-one".