25571331991 has 2 divisors, whose sum is σ = 25571331992. Its totient is φ = 25571331990.

The previous prime is 25571331953. The next prime is 25571332021. The reversal of 25571331991 is 19913317552.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25571331991 - 2³³ = 16981397399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25571331901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12785665995 + 12785665996.

It is an arithmetic number, because the mean of its divisors is an integer number (12785665996).

Almost surely, 2^25571331991 is an apocalyptic number.

25571331991 is a deficient number, since it is larger than the sum of its proper divisors (1).

25571331991 is an equidigital number, since it uses as much as digits as its factorization.

25571331991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 255150, while the sum is 46.

The spelling of 25571331991 in words is "twenty-five billion, five hundred seventy-one million, three hundred thirty-one thousand, nine hundred ninety-one".