78493799781 has 12 divisors (see below), whose sum is σ = 113389211052. Its totient is φ = 52324917696.

The previous prime is 78493799771. The next prime is 78493799819. The reversal of 78493799781 is 18799739487.

It can be written as a sum of positive squares in 2 ways, for example, as 1565784900 + 76928014881 = 39570^2 + 277359^2 .

It is not a de Polignac number, because 78493799781 - 2⁷ = 78493799653 is a prime.

It is a super-2 number, since 2×78493799781² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78493799701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 238696 + ... + 462561.

It is an arithmetic number, because the mean of its divisors is an integer number (9449100921).

Almost surely, 2^78493799781 is an apocalyptic number.

It is an amenable number.

78493799781 is a deficient number, since it is larger than the sum of its proper divisors (34895411271).

78493799781 is a wasteful number, since it uses less digits than its factorization.

78493799781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 713700 (or 713697 counting only the distinct ones).

The product of its digits is 192036096, while the sum is 72.

The spelling of 78493799781 in words is "seventy-eight billion, four hundred ninety-three million, seven hundred ninety-nine thousand, seven hundred eighty-one".