78747788681 has 16 divisors (see below), whose sum is σ = 84527575440. Its totient is φ = 73214668800.

The previous prime is 78747788633. The next prime is 78747788699. The reversal of 78747788681 is 18688774787.

It can be written as a sum of positive squares in 8 ways, for example, as 11855725456 + 66892063225 = 108884^2 + 258635^2 .

It is not a de Polignac number, because 78747788681 - 2¹⁴ = 78747772297 is a prime.

It is a super-2 number, since 2×78747788681² (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 (78747788281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 274220 + ... + 482381.

It is an arithmetic number, because the mean of its divisors is an integer number (5282973465).

Almost surely, 2^78747788681 is an apocalyptic number.

It is an amenable number.

78747788681 is a deficient number, since it is larger than the sum of its proper divisors (5779786759).

78747788681 is a wasteful number, since it uses less digits than its factorization.

78747788681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 756764.

The product of its digits is 236027904, while the sum is 71.

The spelling of 78747788681 in words is "seventy-eight billion, seven hundred forty-seven million, seven hundred eighty-eight thousand, six hundred eighty-one".