81000078 has 16 divisors (see below), whose sum is σ = 170526720. Its totient is φ = 25578936.

The previous prime is 81000077. The next prime is 81000083. The reversal of 81000078 is 87000018.

It is a super-2 number, since 2×81000078² = 13122025272012168, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81000071) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 355150 + ... + 355377.

It is an arithmetic number, because the mean of its divisors is an integer number (10657920).

Almost surely, 2^81000078 is an apocalyptic number.

81000078 is an abundant number, since it is smaller than the sum of its proper divisors (89526642).

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

81000078 is a wasteful number, since it uses less digits than its factorization.

81000078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710551.

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 81000078 is about 9000.0043333323. The cubic root of 81000078 is about 432.6750099755.

The spelling of 81000078 in words is "eighty-one million, seventy-eight", and thus it is an aban number and an uban number.