78149778 has 16 divisors (see below), whose sum is σ = 178628160. Its totient is φ = 22328496.

The previous prime is 78149761. The next prime is 78149779. The reversal of 78149778 is 87794187.

It is a super-2 number, since 2×78149778² = 12214775602898568, 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 78149778.

It is not an unprimeable number, because it can be changed into a prime (78149779) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 930313 + ... + 930396.

It is an arithmetic number, because the mean of its divisors is an integer number (11164260).

Almost surely, 2^78149778 is an apocalyptic number.

78149778 is an abundant number, since it is smaller than the sum of its proper divisors (100478382).

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

78149778 is a wasteful number, since it uses less digits than its factorization.

78149778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1860721.

The product of its digits is 790272, while the sum is 51.

The square root of 78149778 is about 8840.2363090587. The cubic root of 78149778 is about 427.5391763284.

The spelling of 78149778 in words is "seventy-eight million, one hundred forty-nine thousand, seven hundred seventy-eight".