25640661 has 8 divisors (see below), whose sum is σ = 34221600. Its totient is φ = 17076752.

The previous prime is 25640639. The next prime is 25640663. The reversal of 25640661 is 16604652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 25640661 - 2¹³ = 25632469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25640663) 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, 186 + ... + 7163.

It is an arithmetic number, because the mean of its divisors is an integer number (4277700).

Almost surely, 2^25640661 is an apocalyptic number.

It is an amenable number.

25640661 is a deficient number, since it is larger than the sum of its proper divisors (8580939).

25640661 is a wasteful number, since it uses less digits than its factorization.

25640661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8515.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 25640661 is about 5063.6608298740. The cubic root of 25640661 is about 294.8784752729.

The spelling of 25640661 in words is "twenty-five million, six hundred forty thousand, six hundred sixty-one".