25981001 has 2 divisors, whose sum is σ = 25981002. Its totient is φ = 25981000.

The previous prime is 25980953. The next prime is 25981009. The reversal of 25981001 is 10018952.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24492601 + 1488400 = 4949^2 + 1220^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-25981001 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (25981009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12990500 + 12990501.

It is an arithmetic number, because the mean of its divisors is an integer number (12990501).

Almost surely, 2^25981001 is an apocalyptic number.

It is an amenable number.

25981001 is a deficient number, since it is larger than the sum of its proper divisors (1).

25981001 is an equidigital number, since it uses as much as digits as its factorization.

25981001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 25981001 is about 5097.1561679038. The cubic root of 25981001 is about 296.1774296895.

Adding to 25981001 its reverse (10018952), we get a palindrome (35999953).

The spelling of 25981001 in words is "twenty-five million, nine hundred eighty-one thousand, one".