78378731731 has 4 divisors (see below), whose sum is σ = 78473967952. Its totient is φ = 78283495512.

The previous prime is 78378731719. The next prime is 78378731749. The reversal of 78378731731 is 13713787387.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78378731731 - 2⁷ = 78378731603 is a prime.

It is a super-2 number, since 2×78378731731² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78378711731) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47616876 + ... + 47618521.

It is an arithmetic number, because the mean of its divisors is an integer number (19618491988).

Almost surely, 2^78378731731 is an apocalyptic number.

78378731731 is a deficient number, since it is larger than the sum of its proper divisors (95236221).

78378731731 is an equidigital number, since it uses as much as digits as its factorization.

78378731731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95236220.

The product of its digits is 4148928, while the sum is 55.

It can be divided in two parts, 783787 and 31731, that added together give a palindrome (815518).

The spelling of 78378731731 in words is "seventy-eight billion, three hundred seventy-eight million, seven hundred thirty-one thousand, seven hundred thirty-one".