251117107121987 has 2 divisors, whose sum is σ = 251117107121988. Its totient is φ = 251117107121986.

The previous prime is 251117107121953. The next prime is 251117107122017. The reversal of 251117107121987 is 789121701711152.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 251117107121987 - 2¹⁴ = 251117107105603 is a prime.

It is not a weakly prime, because it can be changed into another prime (251117107121917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125558553560993 + 125558553560994.

It is an arithmetic number, because the mean of its divisors is an integer number (125558553560994).

Almost surely, 2^{251117107121987} is an apocalyptic number.

251117107121987 is a deficient number, since it is larger than the sum of its proper divisors (1).

251117107121987 is an equidigital number, since it uses as much as digits as its factorization.

251117107121987 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 493920, while the sum is 53.

The spelling of 251117107121987 in words is "two hundred fifty-one trillion, one hundred seventeen billion, one hundred seven million, one hundred twenty-one thousand, nine hundred eighty-seven".