81361130 has 32 divisors (see below), whose sum is σ = 149590800. Its totient is φ = 31854592.

The previous prime is 81361127. The next prime is 81361139. The reversal of 81361130 is 3116318.

It can be written as a sum of positive squares in 8 ways, for example, as 14661241 + 66699889 = 3829^2 + 8167^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81361096 and 81361105.

It is not an unprimeable number, because it can be changed into a prime (81361139) 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, 100166 + ... + 100974.

Almost surely, 2^81361130 is an apocalyptic number.

81361130 is a deficient number, since it is larger than the sum of its proper divisors (68229670).

81361130 is a wasteful number, since it uses less digits than its factorization.

81361130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 81361130 is about 9020.0404655412. The cubic root of 81361130 is about 433.3169296881.

Adding to 81361130 its reverse (3116318), we get a palindrome (84477448).

The spelling of 81361130 in words is "eighty-one million, three hundred sixty-one thousand, one hundred thirty".