78172128 has 96 divisors (see below), whose sum is σ = 231023520. Its totient is φ = 26034048.

The previous prime is 78172097. The next prime is 78172153. The reversal of 78172128 is 82127187.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×78172128² = 12221763192096768, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 78172092 and 78172101.

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 15 ways as a sum of consecutive naturals, for example, 69426 + ... + 70542.

It is an arithmetic number, because the mean of its divisors is an integer number (2406495).

Almost surely, 2^78172128 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 78172128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115511760).

78172128 is an abundant number, since it is smaller than the sum of its proper divisors (152851392).

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

78172128 is an equidigital number, since it uses as much as digits as its factorization.

78172128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1148 (or 1122 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 78172128 is about 8841.5003251711. The cubic root of 78172128 is about 427.5799296530.

The spelling of 78172128 in words is "seventy-eight million, one hundred seventy-two thousand, one hundred twenty-eight".