78298390817 has 4 divisors (see below), whose sum is σ = 78310637076. Its totient is φ = 78286144560.

The previous prime is 78298390801. The next prime is 78298390853. The reversal of 78298390817 is 71809389287.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 34774417441 + 43523973376 = 186479^2 + 208624^2 .

It is a cyclic number.

It is not a de Polignac number, because 78298390817 - 2⁴ = 78298390801 is a prime.

It is a super-2 number, since 2×78298390817² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78298390817.

It is not an unprimeable number, because it can be changed into a prime (78298390517) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6113534 + ... + 6126327.

It is an arithmetic number, because the mean of its divisors is an integer number (19577659269).

Almost surely, 2^78298390817 is an apocalyptic number.

It is an amenable number.

78298390817 is a deficient number, since it is larger than the sum of its proper divisors (12246259).

78298390817 is a wasteful number, since it uses less digits than its factorization.

78298390817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12246258.

The product of its (nonzero) digits is 12192768, while the sum is 62.

The spelling of 78298390817 in words is "seventy-eight billion, two hundred ninety-eight million, three hundred ninety thousand, eight hundred seventeen".