81032731 has 8 divisors (see below), whose sum is σ = 87954944. Its totient is φ = 74208960.

The previous prime is 81032723. The next prime is 81032759. The reversal of 81032731 is 13723018.

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

It is a cyclic number.

It is not a de Polignac number, because 81032731 - 2³ = 81032723 is a prime.

It is a super-2 number, since 2×81032731² = 13132606986636722, 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 = 81032696 and 81032705.

It is not an unprimeable number, because it can be changed into a prime (81032771) 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, 22890 + ... + 26191.

It is an arithmetic number, because the mean of its divisors is an integer number (10994368).

Almost surely, 2^81032731 is an apocalyptic number.

81032731 is a deficient number, since it is larger than the sum of its proper divisors (6922213).

81032731 is a wasteful number, since it uses less digits than its factorization.

81032731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49221.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 81032731 is about 9001.8182052294. The cubic root of 81032731 is about 432.7331425905.

Adding to 81032731 its reverse (13723018), we get a palindrome (94755749).

The spelling of 81032731 in words is "eighty-one million, thirty-two thousand, seven hundred thirty-one".