81040331 has 2 divisors, whose sum is σ = 81040332. Its totient is φ = 81040330.

The previous prime is 81040321. The next prime is 81040369. The reversal of 81040331 is 13304018.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81040331 - 2¹⁰ = 81039307 is a prime.

It is a super-2 number, since 2×81040331² = 13135070497179122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81040321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40520165 + 40520166.

It is an arithmetic number, because the mean of its divisors is an integer number (40520166).

Almost surely, 2^81040331 is an apocalyptic number.

81040331 is a deficient number, since it is larger than the sum of its proper divisors (1).

81040331 is an equidigital number, since it uses as much as digits as its factorization.

81040331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 81040331 is about 9002.2403322729. The cubic root of 81040331 is about 432.7466707416.

Adding to 81040331 its reverse (13304018), we get a palindrome (94344349).

The spelling of 81040331 in words is "eighty-one million, forty thousand, three hundred thirty-one".