81244491 has 4 divisors (see below), whose sum is σ = 108325992. Its totient is φ = 54162992.

The previous prime is 81244483. The next prime is 81244507. The reversal of 81244491 is 19444218.

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

It is a cyclic number.

It is not a de Polignac number, because 81244491 - 2³ = 81244483 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81244421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13540746 + ... + 13540751.

It is an arithmetic number, because the mean of its divisors is an integer number (27081498).

Almost surely, 2^81244491 is an apocalyptic number.

81244491 is a deficient number, since it is larger than the sum of its proper divisors (27081501).

81244491 is a wasteful number, since it uses less digits than its factorization.

81244491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27081500.

The product of its digits is 9216, while the sum is 33.

The square root of 81244491 is about 9013.5725991418. The cubic root of 81244491 is about 433.1097635031.

The spelling of 81244491 in words is "eighty-one million, two hundred forty-four thousand, four hundred ninety-one".