25640643 has 8 divisors (see below), whose sum is σ = 39071488. Its totient is φ = 14651784.

The previous prime is 25640639. The next prime is 25640663. The reversal of 25640643 is 34604652.

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

It is not a de Polignac number, because 25640643 - 2² = 25640639 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 25640643.

It is not an unprimeable number, because it can be changed into a prime (25640603) 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, 610471 + ... + 610512.

It is an arithmetic number, because the mean of its divisors is an integer number (4883936).

Almost surely, 2^25640643 is an apocalyptic number.

25640643 is a deficient number, since it is larger than the sum of its proper divisors (13430845).

25640643 is a wasteful number, since it uses less digits than its factorization.

25640643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1220993.

The product of its (nonzero) digits is 17280, while the sum is 30.

The square root of 25640643 is about 5063.6590525034. The cubic root of 25640643 is about 294.8784062704.

The spelling of 25640643 in words is "twenty-five million, six hundred forty thousand, six hundred forty-three".