25640681 has 8 divisors (see below), whose sum is σ = 28056000. Its totient is φ = 23239440.

The previous prime is 25640677. The next prime is 25640683. The reversal of 25640681 is 18604652.

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 25640681 - 2² = 25640677 is a prime.

It is a super-2 number, since 2×25640681² = 1314889044287522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (25640683) 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, 500 + ... + 7178.

It is an arithmetic number, because the mean of its divisors is an integer number (3507000).

Almost surely, 2^25640681 is an apocalyptic number.

It is an amenable number.

25640681 is a deficient number, since it is larger than the sum of its proper divisors (2415319).

25640681 is a wasteful number, since it uses less digits than its factorization.

25640681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7039.

The product of its (nonzero) digits is 11520, while the sum is 32.

The square root of 25640681 is about 5063.6628047294. The cubic root of 25640681 is about 294.8785519424.

The spelling of 25640681 in words is "twenty-five million, six hundred forty thousand, six hundred eighty-one".