81180731 has 8 divisors (see below), whose sum is σ = 84817824. Its totient is φ = 77552640.

The previous prime is 81180709. The next prime is 81180733. The reversal of 81180731 is 13708118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81180731 is a prime.

It is a super-2 number, since 2×81180731² = 13180622171388722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81180694 and 81180703.

It is not an unprimeable number, because it can be changed into a prime (81180733) 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, 21755 + ... + 25211.

It is an arithmetic number, because the mean of its divisors is an integer number (10602228).

Almost surely, 2^81180731 is an apocalyptic number.

81180731 is a deficient number, since it is larger than the sum of its proper divisors (3637093).

81180731 is a wasteful number, since it uses less digits than its factorization.

81180731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4501.

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 81180731 is about 9010.0350165801. The cubic root of 81180731 is about 432.9964335392.

Adding to 81180731 its reverse (13708118), we get a palindrome (94888849).

The spelling of 81180731 in words is "eighty-one million, one hundred eighty thousand, seven hundred thirty-one".