81738173 has 16 divisors (see below), whose sum is σ = 91172736. Its totient is φ = 72656640.

The previous prime is 81738169. The next prime is 81738179. The reversal of 81738173 is 37183718.

It is a cyclic number.

It is not a de Polignac number, because 81738173 - 2² = 81738169 is a prime.

It is a super-2 number, since 2×81738173² = 13362257850755858, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81738179) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 109640 + ... + 110382.

It is an arithmetic number, because the mean of its divisors is an integer number (5698296).

Almost surely, 2^81738173 is an apocalyptic number.

It is an amenable number.

81738173 is a deficient number, since it is larger than the sum of its proper divisors (9434563).

81738173 is a wasteful number, since it uses less digits than its factorization.

81738173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 964.

The product of its digits is 28224, while the sum is 38.

The square root of 81738173 is about 9040.9166017611. The cubic root of 81738173 is about 433.9852561408.

The spelling of 81738173 in words is "eighty-one million, seven hundred thirty-eight thousand, one hundred seventy-three".