78799996665 has 40 divisors (see below), whose sum is σ = 152122168968. Its totient is φ = 38793841920.

The previous prime is 78799996663. The next prime is 78799996679. The reversal of 78799996665 is 56669999787.

It can be written as a sum of positive squares in 4 ways, for example, as 5159405241 + 73640591424 = 71829^2 + 271368^2 .

It is not a de Polignac number, because 78799996665 - 2¹ = 78799996663 is a prime.

It is a super-2 number, since 2×78799996665² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is not an unprimeable number, because it can be changed into a prime (78799996663) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 7478116 + ... + 7488645.

Almost surely, 2^78799996665 is an apocalyptic number.

It is an amenable number.

78799996665 is a deficient number, since it is larger than the sum of its proper divisors (73322172303).

78799996665 is a wasteful number, since it uses less digits than its factorization.

78799996665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14966791 (or 14966782 counting only the distinct ones).

The product of its digits is 2777664960, while the sum is 81.

The spelling of 78799996665 in words is "seventy-eight billion, seven hundred ninety-nine million, nine hundred ninety-six thousand, six hundred sixty-five".