78365844 has 18 divisors (see below), whose sum is σ = 198091530. Its totient is φ = 26121936.

The previous prime is 78365827. The next prime is 78365849. The reversal of 78365844 is 44856387.

It can be written as a sum of positive squares in only one way, i.e., 75168900 + 3196944 = 8670^2 + 1788^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×78365844² = 12282411011664672, which contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 78365844.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78365849) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1088379 + ... + 1088450.

It is an arithmetic number, because the mean of its divisors is an integer number (11005085).

Almost surely, 2^78365844 is an apocalyptic number.

It is an amenable number.

78365844 is an abundant number, since it is smaller than the sum of its proper divisors (119725686).

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

78365844 is a wasteful number, since it uses less digits than its factorization.

78365844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2176839 (or 2176834 counting only the distinct ones).

The product of its digits is 645120, while the sum is 45.

The square root of 78365844 is about 8852.4484748571. The cubic root of 78365844 is about 427.9328292992.

The spelling of 78365844 in words is "seventy-eight million, three hundred sixty-five thousand, eight hundred forty-four".