81908746 has 4 divisors (see below), whose sum is σ = 122863122. Its totient is φ = 40954372.

The previous prime is 81908719. The next prime is 81908759. The reversal of 81908746 is 64780918.

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

It can be written as a sum of positive squares in only one way, i.e., 81812025 + 96721 = 9045^2 + 311^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 20477185 + ... + 20477188.

Almost surely, 2^81908746 is an apocalyptic number.

81908746 is a deficient number, since it is larger than the sum of its proper divisors (40954376).

81908746 is a wasteful number, since it uses less digits than its factorization.

81908746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40954375.

The product of its (nonzero) digits is 96768, while the sum is 43.

The square root of 81908746 is about 9050.3450762941. The cubic root of 81908746 is about 434.2869296872.

The spelling of 81908746 in words is "eighty-one million, nine hundred eight thousand, seven hundred forty-six".