81209086 has 16 divisors (see below), whose sum is σ = 139455360. Its totient is φ = 34743960.

The previous prime is 81209081. The next prime is 81209087. The reversal of 81209086 is 68090218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81209081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3981 + ... + 13351.

It is an arithmetic number, because the mean of its divisors is an integer number (8715960).

Almost surely, 2^81209086 is an apocalyptic number.

81209086 is a deficient number, since it is larger than the sum of its proper divisors (58246274).

81209086 is a wasteful number, since it uses less digits than its factorization.

81209086 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9999.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 81209086 is about 9011.6084024995. The cubic root of 81209086 is about 433.0468403477.

The spelling of 81209086 in words is "eighty-one million, two hundred nine thousand, eighty-six".