78042820 has 12 divisors (see below), whose sum is σ = 163889964. Its totient is φ = 31217120.

The previous prime is 78042793. The next prime is 78042829. The reversal of 78042820 is 2824087.

It can be written as a sum of positive squares in 2 ways, for example, as 47306884 + 30735936 = 6878^2 + 5544^2 .

It is not an unprimeable number, because it can be changed into a prime (78042829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1951051 + ... + 1951090.

It is an arithmetic number, because the mean of its divisors is an integer number (13657497).

Almost surely, 2^78042820 is an apocalyptic number.

It is an amenable number.

78042820 is an abundant number, since it is smaller than the sum of its proper divisors (85847144).

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

78042820 is a wasteful number, since it uses less digits than its factorization.

78042820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3902150 (or 3902148 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 31.

The square root of 78042820 is about 8834.1847388426. The cubic root of 78042820 is about 427.3440398688.

The spelling of 78042820 in words is "seventy-eight million, forty-two thousand, eight hundred twenty".