78331840665 has 32 divisors (see below), whose sum is σ = 134989545600. Its totient is φ = 38558294016.

The previous prime is 78331840619. The next prime is 78331840667. The reversal of 78331840665 is 56604813387.

It is not a de Polignac number, because 78331840665 - 2⁷ = 78331840537 is a prime.

It is a super-2 number, since 2×78331840665² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78331840667) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1772761 + ... + 1816409.

It is an arithmetic number, because the mean of its divisors is an integer number (4218423300).

Almost surely, 2^78331840665 is an apocalyptic number.

It is an amenable number.

78331840665 is a deficient number, since it is larger than the sum of its proper divisors (56657704935).

78331840665 is a wasteful number, since it uses less digits than its factorization.

78331840665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52873.

The product of its (nonzero) digits is 2903040, while the sum is 51.

The spelling of 78331840665 in words is "seventy-eight billion, three hundred thirty-one million, eight hundred forty thousand, six hundred sixty-five".