25640001 has 18 divisors (see below), whose sum is σ = 38081862. Its totient is φ = 16623360.

The previous prime is 25639981. The next prime is 25640023. The reversal of 25640001 is 10004652.

It is a happy number.

25640001 is a `hidden beast` number, since 25 + 640 + 0 + 0 + 1 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 12852225 + 12787776 = 3585^2 + 3576^2 .

It is not a de Polignac number, because 25640001 - 2⁶ = 25639937 is a prime.

It is not an unprimeable number, because it can be changed into a prime (25640071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 11281 + ... + 13361.

It is an arithmetic number, because the mean of its divisors is an integer number (2115659).

Almost surely, 2^25640001 is an apocalyptic number.

It is an amenable number.

25640001 is a deficient number, since it is larger than the sum of its proper divisors (12441861).

25640001 is a wasteful number, since it uses less digits than its factorization.

25640001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2161 (or 2121 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 25640001 is about 5063.5956592129. The cubic root of 25640001 is about 294.8759451579.

Adding to 25640001 its reverse (10004652), we get a palindrome (35644653).

The spelling of 25640001 in words is "twenty-five million, six hundred forty thousand, one".