81090906 has 32 divisors (see below), whose sum is σ = 175011648. Its totient is φ = 24900480.

The previous prime is 81090871. The next prime is 81090929. The reversal of 81090906 is 60909018.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60726 + ... + 62046.

It is an arithmetic number, because the mean of its divisors is an integer number (5469114).

Almost surely, 2^81090906 is an apocalyptic number.

81090906 is an abundant number, since it is smaller than the sum of its proper divisors (93920742).

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

81090906 is a wasteful number, since it uses less digits than its factorization.

81090906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2126.

The product of its (nonzero) digits is 3888, while the sum is 33.

The square root of 81090906 is about 9005.0489171353. The cubic root of 81090906 is about 432.8366737123.

The spelling of 81090906 in words is "eighty-one million, ninety thousand, nine hundred six".