81903289 has 8 divisors (see below), whose sum is σ = 88767560. Its totient is φ = 75119616.

The previous prime is 81903277. The next prime is 81903293. The reversal of 81903289 is 98230918.

It can be written as a sum of positive squares in 4 ways, for example, as 5253264 + 76650025 = 2292^2 + 8755^2 .

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

It is not a de Polignac number, because 81903289 - 2¹¹ = 81901241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81903389) 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, 18024 + ... + 22105.

It is an arithmetic number, because the mean of its divisors is an integer number (11095945).

Almost surely, 2^81903289 is an apocalyptic number.

It is an amenable number.

81903289 is a deficient number, since it is larger than the sum of its proper divisors (6864271).

81903289 is a wasteful number, since it uses less digits than its factorization.

81903289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40299.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 81903289 is about 9050.0435910552. The cubic root of 81903289 is about 434.2772849849.

The spelling of 81903289 in words is "eighty-one million, nine hundred three thousand, two hundred eighty-nine".