78694941721 has 16 divisors (see below), whose sum is σ = 86619133440. Its totient is φ = 70900836480.

The previous prime is 78694941697. The next prime is 78694941763. The reversal of 78694941721 is 12714949687.

It is a cyclic number.

It is not a de Polignac number, because 78694941721 - 2¹⁵ = 78694908953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78694971721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 871735 + ... + 957763.

It is an arithmetic number, because the mean of its divisors is an integer number (5413695840).

Almost surely, 2^78694941721 is an apocalyptic number.

It is an amenable number.

78694941721 is a deficient number, since it is larger than the sum of its proper divisors (7924191719).

78694941721 is a wasteful number, since it uses less digits than its factorization.

78694941721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86784.

The product of its digits is 6096384, while the sum is 58.

The spelling of 78694941721 in words is "seventy-eight billion, six hundred ninety-four million, nine hundred forty-one thousand, seven hundred twenty-one".