78171840 has 84 divisors (see below), whose sum is σ = 268888464. Its totient is φ = 20845056.

The previous prime is 78171827. The next prime is 78171851. The reversal of 78171840 is 4817187.

It is a super-2 number, since 2×78171840² = 12221673137971200, 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 = 78171795 and 78171804.

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 11 ways as a sum of consecutive naturals, for example, 10692 + ... + 16451.

Almost surely, 2^78171840 is an apocalyptic number.

It is an amenable number.

78171840 is an abundant number, since it is smaller than the sum of its proper divisors (190716624).

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

78171840 is a wasteful number, since it uses less digits than its factorization.

78171840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27166 (or 27153 counting only the distinct ones).

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

The square root of 78171840 is about 8841.4840383275. The cubic root of 78171840 is about 427.5794045589.

The spelling of 78171840 in words is "seventy-eight million, one hundred seventy-one thousand, eight hundred forty".