78218887666831 has 8 divisors (see below), whose sum is σ = 78986616718464. Its totient is φ = 77451318661080.

The previous prime is 78218887666823. The next prime is 78218887666853. The reversal of 78218887666831 is 13866678881287.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78218887666831 - 2³ = 78218887666823 is a prime.

It is a super-2 number, since 2×78218887666831² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78218887669831) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39029101 + ... + 40984246.

It is an arithmetic number, because the mean of its divisors is an integer number (9873327089808).

Almost surely, 2^{78218887666831} is an apocalyptic number.

78218887666831 is a deficient number, since it is larger than the sum of its proper divisors (767729051633).

78218887666831 is a wasteful number, since it uses less digits than its factorization.

78218887666831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80022941.

The product of its digits is 2080899072, while the sum is 79.

The spelling of 78218887666831 in words is "seventy-eight trillion, two hundred eighteen billion, eight hundred eighty-seven million, six hundred sixty-six thousand, eight hundred thirty-one".