81681046 has 4 divisors (see below), whose sum is σ = 122521572. Its totient is φ = 40840522.

The previous prime is 81681011. The next prime is 81681059. The reversal of 81681046 is 64018618.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20420260 + ... + 20420263.

It is an arithmetic number, because the mean of its divisors is an integer number (30630393).

Almost surely, 2^81681046 is an apocalyptic number.

81681046 is a deficient number, since it is larger than the sum of its proper divisors (40840526).

81681046 is a wasteful number, since it uses less digits than its factorization.

81681046 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40840525.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 81681046 is about 9037.7566906838. The cubic root of 81681046 is about 433.8841281413.

The spelling of 81681046 in words is "eighty-one million, six hundred eighty-one thousand, forty-six".