81143738 has 16 divisors (see below), whose sum is σ = 134622600. Its totient is φ = 36438336.

The previous prime is 81143731. The next prime is 81143749. The reversal of 81143738 is 83734118.

It can be written as a sum of positive squares in 4 ways, for example, as 71859529 + 9284209 = 8477^2 + 3047^2 .

It is a super-2 number, since 2×81143738² = 13168612433225288, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81143698 and 81143707.

It is not an unprimeable number, because it can be changed into a prime (81143731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41213 + ... + 43136.

Almost surely, 2^81143738 is an apocalyptic number.

81143738 is a deficient number, since it is larger than the sum of its proper divisors (53478862).

81143738 is a wasteful number, since it uses less digits than its factorization.

81143738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84401.

The product of its digits is 16128, while the sum is 35.

The square root of 81143738 is about 9007.9819049552. The cubic root of 81143738 is about 432.9306532712.

The spelling of 81143738 in words is "eighty-one million, one hundred forty-three thousand, seven hundred thirty-eight".