78171904 has 72 divisors (see below), whose sum is σ = 163356480. Its totient is φ = 37306368.

The previous prime is 78171901. The next prime is 78171911. The reversal of 78171904 is 40917187.

It is a super-2 number, since 2×78171904² = 12221693149970432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78171901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 878292 + ... + 878380.

It is an arithmetic number, because the mean of its divisors is an integer number (2268840).

Almost surely, 2^78171904 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 78171904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81678240).

78171904 is an abundant number, since it is smaller than the sum of its proper divisors (85184576).

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

78171904 is an equidigital number, since it uses as much as digits as its factorization.

78171904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 78171904 is about 8841.4876576287. The cubic root of 78171904 is about 427.5795212465.

The spelling of 78171904 in words is "seventy-eight million, one hundred seventy-one thousand, nine hundred four".