81040739 has 8 divisors (see below), whose sum is σ = 87793440. Its totient is φ = 74804808.

The previous prime is 81040711. The next prime is 81040747. The reversal of 81040739 is 93704018.

It is not a de Polignac number, because 81040739 - 2⁸ = 81040483 is a prime.

It is a super-2 number, since 2×81040739² = 13135202755332242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81040769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16247 + ... + 20640.

It is an arithmetic number, because the mean of its divisors is an integer number (10974180).

Almost surely, 2^81040739 is an apocalyptic number.

81040739 is a deficient number, since it is larger than the sum of its proper divisors (6752701).

81040739 is an equidigital number, since it uses as much as digits as its factorization.

81040739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36926 (or 36900 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 81040739 is about 9002.2629932701. The cubic root of 81040739 is about 432.7473969658.

The spelling of 81040739 in words is "eighty-one million, forty thousand, seven hundred thirty-nine".