81831245 has 4 divisors (see below), whose sum is σ = 98197500. Its totient is φ = 65464992.

The previous prime is 81831229. The next prime is 81831259. The reversal of 81831245 is 54213818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 33570436 + 48260809 = 5794^2 + 6947^2 .

It is a cyclic number.

It is not a de Polignac number, because 81831245 - 2⁴ = 81831229 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8183120 + ... + 8183129.

It is an arithmetic number, because the mean of its divisors is an integer number (24549375).

Almost surely, 2^81831245 is an apocalyptic number.

It is an amenable number.

81831245 is a deficient number, since it is larger than the sum of its proper divisors (16366255).

81831245 is a wasteful number, since it uses less digits than its factorization.

81831245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16366254.

The product of its digits is 7680, while the sum is 32.

The square root of 81831245 is about 9046.0624030569. The cubic root of 81831245 is about 434.1499142318.

The spelling of 81831245 in words is "eighty-one million, eight hundred thirty-one thousand, two hundred forty-five".