78172728 has 32 divisors (see below), whose sum is σ = 195653760. Its totient is φ = 26028000.

The previous prime is 78172711. The next prime is 78172733. The reversal of 78172728 is 82727187.

It is a super-2 number, since 2×78172728² = 12221950805923968, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78172728.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33603 + ... + 35853.

It is an arithmetic number, because the mean of its divisors is an integer number (6114180).

Almost surely, 2^78172728 is an apocalyptic number.

It is an amenable number.

78172728 is an abundant number, since it is smaller than the sum of its proper divisors (117481032).

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

78172728 is a wasteful number, since it uses less digits than its factorization.

78172728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3707 (or 3703 counting only the distinct ones).

The product of its digits is 87808, while the sum is 42.

The square root of 78172728 is about 8841.5342559988. The cubic root of 78172728 is about 427.5810235949.

The spelling of 78172728 in words is "seventy-eight million, one hundred seventy-two thousand, seven hundred twenty-eight".