78864523920 has 720 divisors, whose sum is σ = 333405504432. Its totient is φ = 16558940160.

The previous prime is 78864523919. The next prime is 78864523939. The reversal of 78864523920 is 2932546887.

It can be written as a sum of positive squares in 8 ways, for example, as 8584393104 + 70280130816 = 92652^2 + 265104^2 .

It is a tau number, because it is divible by the number of its divisors (720).

It is a super-2 number, since 2×78864523920² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 171072490 + ... + 171072950.

Almost surely, 2^78864523920 is an apocalyptic number.

78864523920 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78864523920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (166702752216).

78864523920 is an abundant number, since it is smaller than the sum of its proper divisors (254540980512).

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

78864523920 is a wasteful number, since it uses less digits than its factorization.

78864523920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 880 (or 864 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 54.

The spelling of 78864523920 in words is "seventy-eight billion, eight hundred sixty-four million, five hundred twenty-three thousand, nine hundred twenty".