78397720 has 16 divisors (see below), whose sum is σ = 176394960. Its totient is φ = 31359072.

The previous prime is 78397687. The next prime is 78397721. The reversal of 78397720 is 2779387.

It is a super-2 number, since 2×78397720² = 12292405002396800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78397721) 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, 979932 + ... + 980011.

It is an arithmetic number, because the mean of its divisors is an integer number (11024685).

Almost surely, 2^78397720 is an apocalyptic number.

It is an amenable number.

78397720 is an abundant number, since it is smaller than the sum of its proper divisors (97997240).

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

78397720 is a wasteful number, since it uses less digits than its factorization.

78397720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1959954 (or 1959950 counting only the distinct ones).

The product of its (nonzero) digits is 148176, while the sum is 43.

The square root of 78397720 is about 8854.2486976592. The cubic root of 78397720 is about 427.9908432548.

The spelling of 78397720 in words is "seventy-eight million, three hundred ninety-seven thousand, seven hundred twenty".