81159906 has 16 divisors (see below), whose sum is σ = 170863200. Its totient is φ = 25629408.

The previous prime is 81159899. The next prime is 81159919. The reversal of 81159906 is 60995118.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 355851 + ... + 356078.

It is an arithmetic number, because the mean of its divisors is an integer number (10678950).

Almost surely, 2^81159906 is an apocalyptic number.

81159906 is an abundant number, since it is smaller than the sum of its proper divisors (89703294).

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

81159906 is a wasteful number, since it uses less digits than its factorization.

81159906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 711953.

The product of its (nonzero) digits is 19440, while the sum is 39.

The square root of 81159906 is about 9008.8792865706. The cubic root of 81159906 is about 432.9594053685.

The spelling of 81159906 in words is "eighty-one million, one hundred fifty-nine thousand, nine hundred six".