78390442 has 32 divisors (see below), whose sum is σ = 130846464. Its totient is φ = 34992000.

The previous prime is 78390439. The next prime is 78390479. The reversal of 78390442 is 24409387.

It is a happy number.

It is a super-2 number, since 2×78390442² = 12290122793910728, which contains 22 as substring.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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 15 ways as a sum of consecutive naturals, for example, 160723 + ... + 161209.

It is an arithmetic number, because the mean of its divisors is an integer number (4088952).

Almost surely, 2^78390442 is an apocalyptic number.

78390442 is a deficient number, since it is larger than the sum of its proper divisors (52456022).

78390442 is a wasteful number, since it uses less digits than its factorization.

78390442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694.

The product of its (nonzero) digits is 48384, while the sum is 37.

The square root of 78390442 is about 8853.8376989868. The cubic root of 78390442 is about 427.9775987635.

The spelling of 78390442 in words is "seventy-eight million, three hundred ninety thousand, four hundred forty-two".