78171940 has 96 divisors (see below), whose sum is σ = 213663744. Its totient is φ = 23295360.

The previous prime is 78171937. The next prime is 78171943. The reversal of 78171940 is 4917187.

It is an interprime number because it is at equal distance from previous prime (78171937) and next prime (78171943).

It is a super-2 number, since 2×78171940² = 12221704406727200, 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 78171940.

It is not an unprimeable number, because it can be changed into a prime (78171943) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 34317 + ... + 36523.

It is an arithmetic number, because the mean of its divisors is an integer number (2225664).

Almost surely, 2^78171940 is an apocalyptic number.

78171940 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78171940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106831872).

78171940 is an abundant number, since it is smaller than the sum of its proper divisors (135491804).

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

78171940 is a wasteful number, since it uses less digits than its factorization.

78171940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2257 (or 2255 counting only the distinct ones).

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

The square root of 78171940 is about 8841.4896934849. The cubic root of 78171940 is about 427.5795868833.

The spelling of 78171940 in words is "seventy-eight million, one hundred seventy-one thousand, nine hundred forty".