78451939920 has 40 divisors (see below), whose sum is σ = 243201014496. Its totient is φ = 20920517248.

The previous prime is 78451939897. The next prime is 78451939933. The reversal of 78451939920 is 2993915487.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×78451939920² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 163441302 + ... + 163441781.

Almost surely, 2^78451939920 is an apocalyptic number.

It is an amenable number.

78451939920 is an abundant number, since it is smaller than the sum of its proper divisors (164749074576).

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

78451939920 is a wasteful number, since it uses less digits than its factorization.

78451939920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326883099 (or 326883093 counting only the distinct ones).

The product of its (nonzero) digits is 4898880, while the sum is 57.

The spelling of 78451939920 in words is "seventy-eight billion, four hundred fifty-one million, nine hundred thirty-nine thousand, nine hundred twenty".