25951721897 has 2 divisors, whose sum is σ = 25951721898. Its totient is φ = 25951721896.

The previous prime is 25951721879. The next prime is 25951721903. The reversal of 25951721897 is 79812715952.

Together with previous prime (25951721879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 24564606361 + 1387115536 = 156731^2 + 37244^2 .

It is a cyclic number.

It is not a de Polignac number, because 25951721897 - 2⁶ = 25951721833 is a prime.

It is not a weakly prime, because it can be changed into another prime (25951727897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12975860948 + 12975860949.

It is an arithmetic number, because the mean of its divisors is an integer number (12975860949).

Almost surely, 2^25951721897 is an apocalyptic number.

It is an amenable number.

25951721897 is a deficient number, since it is larger than the sum of its proper divisors (1).

25951721897 is an equidigital number, since it uses as much as digits as its factorization.

25951721897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3175200, while the sum is 56.

The spelling of 25951721897 in words is "twenty-five billion, nine hundred fifty-one million, seven hundred twenty-one thousand, eight hundred ninety-seven".