78312753781 has 6 divisors (see below), whose sum is σ = 80486520450. Its totient is φ = 76196191536.

The previous prime is 78312753773. The next prime is 78312753787. The reversal of 78312753781 is 18735721387.

It can be written as a sum of positive squares in 3 ways, for example, as 68003600625 + 10309153156 = 260775^2 + 101534^2 .

It is not a de Polignac number, because 78312753781 - 2³ = 78312753773 is a prime.

It is a super-2 number, since 2×78312753781² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78312753787) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 28600806 + ... + 28603543.

It is an arithmetic number, because the mean of its divisors is an integer number (13414420075).

Almost surely, 2^78312753781 is an apocalyptic number.

It is an amenable number.

78312753781 is a deficient number, since it is larger than the sum of its proper divisors (2173766669).

78312753781 is an equidigital number, since it uses as much as digits as its factorization.

78312753781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57204423 (or 57204386 counting only the distinct ones).

The product of its digits is 1975680, while the sum is 52.

The spelling of 78312753781 in words is "seventy-eight billion, three hundred twelve million, seven hundred fifty-three thousand, seven hundred eighty-one".