81836172 has 54 divisors (see below), whose sum is σ = 227391164. Its totient is φ = 24797520.

The previous prime is 81836141. The next prime is 81836177. The reversal of 81836172 is 27163818.

It is a super-2 number, since 2×81836172² = 13394318095227168, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (81836177) by changing a digit.

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 in 17 ways as a sum of consecutive naturals, for example, 5038 + ... + 13749.

Almost surely, 2^81836172 is an apocalyptic number.

It is an amenable number.

81836172 is an abundant number, since it is smaller than the sum of its proper divisors (145554992).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81836172 is a wasteful number, since it uses less digits than its factorization.

81836172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18819 (or 18803 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 81836172 is about 9046.3347273910. The cubic root of 81836172 is about 434.1586273409.

The spelling of 81836172 in words is "eighty-one million, eight hundred thirty-six thousand, one hundred seventy-two".