25681409 has 12 divisors (see below), whose sum is σ = 29022336. Its totient is φ = 22671792.

The previous prime is 25681393. The next prime is 25681451. The reversal of 25681409 is 90418652.

It is not a de Polignac number, because 25681409 - 2⁴ = 25681393 is a prime.

It is a super-4 number, since 4×25681409⁴ (a number of 31 digits) contains 4444 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25681459) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 584 + ... + 7190.

It is an arithmetic number, because the mean of its divisors is an integer number (2418528).

Almost surely, 2^25681409 is an apocalyptic number.

It is an amenable number.

25681409 is a deficient number, since it is larger than the sum of its proper divisors (3340927).

25681409 is a wasteful number, since it uses less digits than its factorization.

25681409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6656 (or 6643 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 25681409 is about 5067.6828038069. The cubic root of 25681409 is about 295.0345990253.

The spelling of 25681409 in words is "twenty-five million, six hundred eighty-one thousand, four hundred nine".