78688216821 has 8 divisors (see below), whose sum is σ = 104954356864. Its totient is φ = 52440444000.

The previous prime is 78688216801. The next prime is 78688216847. The reversal of 78688216821 is 12861288687.

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

It is not a de Polignac number, because 78688216821 - 2¹⁸ = 78687954677 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 (78688216801) 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, 4581805 + ... + 4598946.

It is an arithmetic number, because the mean of its divisors is an integer number (13119294608).

Almost surely, 2^78688216821 is an apocalyptic number.

It is an amenable number.

78688216821 is a deficient number, since it is larger than the sum of its proper divisors (26266140043).

78688216821 is a wasteful number, since it uses less digits than its factorization.

78688216821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9183611.

The product of its digits is 4128768, while the sum is 57.

The spelling of 78688216821 in words is "seventy-eight billion, six hundred eighty-eight million, two hundred sixteen thousand, eight hundred twenty-one".