81309017 has 6 divisors (see below), whose sum is σ = 83567358. Its totient is φ = 79110144.

The previous prime is 81308971. The next prime is 81309029. The reversal of 81309017 is 71090318.

It can be written as a sum of positive squares in 3 ways, for example, as 33131536 + 48177481 = 5756^2 + 6941^2 .

It is not a de Polignac number, because 81309017 - 2⁸ = 81308761 is a prime.

It is a super-2 number, since 2×81309017² = 13222312491012578, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81309047) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 28328 + ... + 31065.

It is an arithmetic number, because the mean of its divisors is an integer number (13927893).

Almost surely, 2^81309017 is an apocalyptic number.

It is an amenable number.

81309017 is a deficient number, since it is larger than the sum of its proper divisors (2258341).

81309017 is an equidigital number, since it uses as much as digits as its factorization.

81309017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59467 (or 59430 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 29.

The square root of 81309017 is about 9017.1512685548. The cubic root of 81309017 is about 433.2243946404.

The spelling of 81309017 in words is "eighty-one million, three hundred nine thousand, seventeen".