25650471991 has 2 divisors, whose sum is σ = 25650471992. Its totient is φ = 25650471990.

The previous prime is 25650471961. The next prime is 25650472009. The reversal of 25650471991 is 19917405652.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 25650471991 - 2³¹ = 23502988343 is a prime.

It is a super-2 number, since 2×25650471991² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (25650471901) 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, 12825235995 + 12825235996.

It is an arithmetic number, because the mean of its divisors is an integer number (12825235996).

Almost surely, 2^25650471991 is an apocalyptic number.

25650471991 is a deficient number, since it is larger than the sum of its proper divisors (1).

25650471991 is an equidigital number, since it uses as much as digits as its factorization.

25650471991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 680400, while the sum is 49.

The spelling of 25650471991 in words is "twenty-five billion, six hundred fifty million, four hundred seventy-one thousand, nine hundred ninety-one".