25991001 has 12 divisors (see below), whose sum is σ = 37761828. Its totient is φ = 17226144.

The previous prime is 25990997. The next prime is 25991023. The reversal of 25991001 is 10019952.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12595401 + 13395600 = 3549^2 + 3660^2 .

It is not a de Polignac number, because 25991001 - 2² = 25990997 is a prime.

It is not an unprimeable number, because it can be changed into a prime (25991071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6790 + ... + 9903.

It is an arithmetic number, because the mean of its divisors is an integer number (3146819).

Almost surely, 2^25991001 is an apocalyptic number.

It is an amenable number.

25991001 is a deficient number, since it is larger than the sum of its proper divisors (11770827).

25991001 is a wasteful number, since it uses less digits than its factorization.

25991001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16872 (or 16869 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 25991001 is about 5098.1370126743. The cubic root of 25991001 is about 296.2154240478.

It can be divided in two parts, 2599 and 1001, that added together give a square (3600 = 60²).

The spelling of 25991001 in words is "twenty-five million, nine hundred ninety-one thousand, one".