78369396640 has 24 divisors (see below), whose sum is σ = 185147699940. Its totient is φ = 31347758592.

The previous prime is 78369396617. The next prime is 78369396647. The reversal of 78369396640 is 4669396387.

It can be written as a sum of positive squares in 2 ways, for example, as 75490859536 + 2878537104 = 274756^2 + 53652^2 .

It is a super-2 number, since 2×78369396640² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78369396647) 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, 244904205 + ... + 244904524.

Almost surely, 2^78369396640 is an apocalyptic number.

It is an amenable number.

78369396640 is an abundant number, since it is smaller than the sum of its proper divisors (106778303300).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78369396640 is a wasteful number, since it uses less digits than its factorization.

78369396640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 489808744 (or 489808736 counting only the distinct ones).

The product of its (nonzero) digits is 35271936, while the sum is 61.

The spelling of 78369396640 in words is "seventy-eight billion, three hundred sixty-nine million, three hundred ninety-six thousand, six hundred forty".