81440104 has 16 divisors (see below), whose sum is σ = 156425220. Its totient is φ = 39726720.

The previous prime is 81440101. The next prime is 81440123. The reversal of 81440104 is 40104418.

It can be written as a sum of positive squares in 2 ways, for example, as 80964004 + 476100 = 8998^2 + 690^2 .

It is not an unprimeable number, because it can be changed into a prime (81440101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 123819 + ... + 124474.

Almost surely, 2^81440104 is an apocalyptic number.

It is an amenable number.

81440104 is a deficient number, since it is larger than the sum of its proper divisors (74985116).

81440104 is a wasteful number, since it uses less digits than its factorization.

81440104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 248340 (or 248336 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 22.

The square root of 81440104 is about 9024.4171002896. The cubic root of 81440104 is about 433.4570854968.

The spelling of 81440104 in words is "eighty-one million, four hundred forty thousand, one hundred four".