78406665907 has 4 divisors (see below), whose sum is σ = 78412378240. Its totient is φ = 78400953576.

The previous prime is 78406665901. The next prime is 78406665943. The reversal of 78406665907 is 70956660487.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70956660487 = 997 ⋅71170171.

It is a cyclic number.

It is not a de Polignac number, because 78406665907 - 2²⁷ = 78272448179 is a prime.

It is a super-2 number, since 2×78406665907² (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 (78406665901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2835528 + ... + 2863045.

It is an arithmetic number, because the mean of its divisors is an integer number (19603094560).

Almost surely, 2^78406665907 is an apocalyptic number.

78406665907 is a deficient number, since it is larger than the sum of its proper divisors (5712333).

78406665907 is a wasteful number, since it uses less digits than its factorization.

78406665907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5712332.

The product of its (nonzero) digits is 15240960, while the sum is 58.

The spelling of 78406665907 in words is "seventy-eight billion, four hundred six million, six hundred sixty-five thousand, nine hundred seven".