78172458 has 64 divisors (see below), whose sum is σ = 199100160. Its totient is φ = 19901952.

The previous prime is 78172439. The next prime is 78172489. The reversal of 78172458 is 85427187.

It is a super-2 number, since 2×78172458² = 12221866379523528, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon 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 31 ways as a sum of consecutive naturals, for example, 13366 + ... + 18302.

It is an arithmetic number, because the mean of its divisors is an integer number (3110940).

Almost surely, 2^78172458 is an apocalyptic number.

78172458 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 78172458, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99550080).

78172458 is an abundant number, since it is smaller than the sum of its proper divisors (120927702).

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

78172458 is a wasteful number, since it uses less digits than its factorization.

78172458 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4991.

The product of its digits is 125440, while the sum is 42.

The square root of 78172458 is about 8841.5189871424. The cubic root of 78172458 is about 427.5805313217.

The spelling of 78172458 in words is "seventy-eight million, one hundred seventy-two thousand, four hundred fifty-eight".