78999628991 has 4 divisors (see below), whose sum is σ = 79122873984. Its totient is φ = 78876384000.

The previous prime is 78999628969. The next prime is 78999629029. The reversal of 78999628991 is 19982699987.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 78999628991 - 2¹⁴ = 78999612607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78999628901) 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, 61621535 + ... + 61622816.

It is an arithmetic number, because the mean of its divisors is an integer number (19780718496).

Almost surely, 2^78999628991 is an apocalyptic number.

78999628991 is a deficient number, since it is larger than the sum of its proper divisors (123244993).

78999628991 is a wasteful number, since it uses less digits than its factorization.

78999628991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123244992.

The product of its digits is 317447424, while the sum is 77.

The spelling of 78999628991 in words is "seventy-eight billion, nine hundred ninety-nine million, six hundred twenty-eight thousand, nine hundred ninety-one".