81851722 has 16 divisors (see below), whose sum is σ = 125741952. Its totient is φ = 39942720.

The previous prime is 81851701. The next prime is 81851723. The reversal of 81851722 is 22715818.

It is not an unprimeable number, because it can be changed into a prime (81851723) 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 7 ways as a sum of consecutive naturals, for example, 39697 + ... + 41707.

It is an arithmetic number, because the mean of its divisors is an integer number (7858872).

Almost surely, 2^81851722 is an apocalyptic number.

81851722 is a deficient number, since it is larger than the sum of its proper divisors (43890230).

81851722 is a wasteful number, since it uses less digits than its factorization.

81851722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2493.

The product of its digits is 8960, while the sum is 34.

The square root of 81851722 is about 9047.1941506746. The cubic root of 81851722 is about 434.1861243060.

The spelling of 81851722 in words is "eighty-one million, eight hundred fifty-one thousand, seven hundred twenty-two".