78549978 has 32 divisors (see below), whose sum is σ = 170755200. Its totient is φ = 23944896.

The previous prime is 78549967. The next prime is 78549983. The reversal of 78549978 is 87994587.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3883 + ... + 13121.

It is an arithmetic number, because the mean of its divisors is an integer number (5336100).

Almost surely, 2^78549978 is an apocalyptic number.

78549978 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 78549978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85377600).

78549978 is an abundant number, since it is smaller than the sum of its proper divisors (92205222).

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

78549978 is a wasteful number, since it uses less digits than its factorization.

78549978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9366.

The product of its digits is 5080320, while the sum is 57.

The square root of 78549978 is about 8862.8425462715. The cubic root of 78549978 is about 428.2677343391.

The spelling of 78549978 in words is "seventy-eight million, five hundred forty-nine thousand, nine hundred seventy-eight".