81291306 has 8 divisors (see below), whose sum is σ = 162582624. Its totient is φ = 27097100.

The previous prime is 81291299. The next prime is 81291307. The reversal of 81291306 is 60319218.

It is a sphenic number, since it is the product of 3 distinct primes.

81291306 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (81291307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6774270 + ... + 6774281.

It is an arithmetic number, because the mean of its divisors is an integer number (20322828).

Almost surely, 2^81291306 is an apocalyptic number.

81291306 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81291306 is a wasteful number, since it uses less digits than its factorization.

81291306 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13548556.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 81291306 is about 9016.1691421579. The cubic root of 81291306 is about 433.1929368976.

The spelling of 81291306 in words is "eighty-one million, two hundred ninety-one thousand, three hundred six".