78117401491 has 2 divisors, whose sum is σ = 78117401492. Its totient is φ = 78117401490.

The previous prime is 78117401489. The next prime is 78117401497. The reversal of 78117401491 is 19410471187.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78117401491 - 2¹ = 78117401489 is a prime.

It is a super-2 number, since 2×78117401491² (a number of 23 digits) contains 22 as substring.

Together with 78117401489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (78117401497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39058700745 + 39058700746.

It is an arithmetic number, because the mean of its divisors is an integer number (39058700746).

Almost surely, 2^78117401491 is an apocalyptic number.

78117401491 is a deficient number, since it is larger than the sum of its proper divisors (1).

78117401491 is an equidigital number, since it uses as much as digits as its factorization.

78117401491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56448, while the sum is 43.

The spelling of 78117401491 in words is "seventy-eight billion, one hundred seventeen million, four hundred one thousand, four hundred ninety-one".