81809914 has 8 divisors (see below), whose sum is σ = 122758740. Its totient is φ = 40890336.

The previous prime is 81809911. The next prime is 81809921. The reversal of 81809914 is 41990818.

It can be written as a sum of positive squares in 2 ways, for example, as 78623689 + 3186225 = 8867^2 + 1785^2 .

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

It is not an unprimeable number, because it can be changed into a prime (81809911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2112 + ... + 12964.

Almost surely, 2^81809914 is an apocalyptic number.

81809914 is a deficient number, since it is larger than the sum of its proper divisors (40948826).

81809914 is a wasteful number, since it uses less digits than its factorization.

81809914 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14624.

The product of its (nonzero) digits is 20736, while the sum is 40.

The square root of 81809914 is about 9044.8833049410. The cubic root of 81809914 is about 434.1121875802.

The spelling of 81809914 in words is "eighty-one million, eight hundred nine thousand, nine hundred fourteen".