78418081 has 12 divisors (see below), whose sum is σ = 91530372. Its totient is φ = 66987648.

The previous prime is 78418061. The next prime is 78418091. The reversal of 78418081 is 18081487.

It can be written as a sum of positive squares in 2 ways, for example, as 625681 + 77792400 = 791^2 + 8820^2 .

It is not a de Polignac number, because 78418081 - 2⁵ = 78418049 is a prime.

It is a super-2 number, since 2×78418081² = 12298790855445122, which contains 22 as substring.

It is a Duffinian number.

78418081 is a modest number, since divided by 18081 gives 784 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 78418081.

It is not an unprimeable number, because it can be changed into a prime (78418031) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12781 + ... + 17893.

It is an arithmetic number, because the mean of its divisors is an integer number (7627531).

Almost surely, 2^78418081 is an apocalyptic number.

78418081 is the 5113-rd octagonal number.

It is an amenable number.

78418081 is a deficient number, since it is larger than the sum of its proper divisors (13112291).

78418081 is a wasteful number, since it uses less digits than its factorization.

78418081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5440 (or 5433 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 37.

The square root of 78418081 is about 8855.3984100096. The cubic root of 78418081 is about 428.0278918120.

The spelling of 78418081 in words is "seventy-eight million, four hundred eighteen thousand, eighty-one".