78240720 has 80 divisors (see below), whose sum is σ = 247162752. Its totient is φ = 20467200.

The previous prime is 78240709. The next prime is 78240739. The reversal of 78240720 is 2704287.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×78240720² = 12243220532236800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9645 + ... + 15795.

Almost surely, 2^78240720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78240720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123581376).

78240720 is an abundant number, since it is smaller than the sum of its proper divisors (168922032).

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

78240720 is a wasteful number, since it uses less digits than its factorization.

78240720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6220 (or 6214 counting only the distinct ones).

The product of its (nonzero) digits is 6272, while the sum is 30.

The square root of 78240720 is about 8845.3784543116. The cubic root of 78240720 is about 427.7049528523.

The spelling of 78240720 in words is "seventy-eight million, two hundred forty thousand, seven hundred twenty".