81807249 has 16 divisors (see below), whose sum is σ = 111590784. Its totient is φ = 53289600.

The previous prime is 81807223. The next prime is 81807263. The reversal of 81807249 is 94270818.

It is not a de Polignac number, because 81807249 - 2⁸ = 81806993 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81807269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43764 + ... + 45594.

It is an arithmetic number, because the mean of its divisors is an integer number (6974424).

Almost surely, 2^81807249 is an apocalyptic number.

It is an amenable number.

81807249 is a deficient number, since it is larger than the sum of its proper divisors (29783535).

81807249 is a wasteful number, since it uses less digits than its factorization.

81807249 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2168.

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 81807249 is about 9044.7359828798. The cubic root of 81807249 is about 434.1074737198.

The spelling of 81807249 in words is "eighty-one million, eight hundred seven thousand, two hundred forty-nine".