78865745731 has 2 divisors, whose sum is σ = 78865745732. Its totient is φ = 78865745730.

The previous prime is 78865745729. The next prime is 78865745809. The reversal of 78865745731 is 13754756887.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78865745731 - 2¹ = 78865745729 is a prime.

It is a super-2 number, since 2×78865745731² (a number of 23 digits) contains 22 as substring.

Together with 78865745729, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 78865745731.

It is not a weakly prime, because it can be changed into another prime (78865742731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39432872865 + 39432872866.

It is an arithmetic number, because the mean of its divisors is an integer number (39432872866).

Almost surely, 2^78865745731 is an apocalyptic number.

78865745731 is a deficient number, since it is larger than the sum of its proper divisors (1).

78865745731 is an equidigital number, since it uses as much as digits as its factorization.

78865745731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 39513600, while the sum is 61.

The spelling of 78865745731 in words is "seventy-eight billion, eight hundred sixty-five million, seven hundred forty-five thousand, seven hundred thirty-one".