81162681 has 16 divisors (see below), whose sum is σ = 111951360. Its totient is φ = 52248960.

The previous prime is 81162673. The next prime is 81162707. The reversal of 81162681 is 18626118.

It is not a de Polignac number, because 81162681 - 2³ = 81162673 is a prime.

It is a super-2 number, since 2×81162681² = 13174761574215522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81162611) 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, 71325 + ... + 72453.

It is an arithmetic number, because the mean of its divisors is an integer number (6996960).

Almost surely, 2^81162681 is an apocalyptic number.

It is an amenable number.

81162681 is a deficient number, since it is larger than the sum of its proper divisors (30788679).

81162681 is a wasteful number, since it uses less digits than its factorization.

81162681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1936.

The product of its digits is 4608, while the sum is 33.

The square root of 81162681 is about 9009.0332999718. The cubic root of 81162681 is about 432.9643398603.

Adding to 81162681 its reverse (18626118), we get a palindrome (99788799).

The spelling of 81162681 in words is "eighty-one million, one hundred sixty-two thousand, six hundred eighty-one".