81245247 has 8 divisors (see below), whose sum is σ = 109118256. Its totient is φ = 53767872.

The previous prime is 81245243. The next prime is 81245287. The reversal of 81245247 is 74254218.

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

It is not a de Polignac number, because 81245247 - 2² = 81245243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81245243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98428 + ... + 99249.

It is an arithmetic number, because the mean of its divisors is an integer number (13639782).

Almost surely, 2^81245247 is an apocalyptic number.

81245247 is a deficient number, since it is larger than the sum of its proper divisors (27873009).

81245247 is a wasteful number, since it uses less digits than its factorization.

81245247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197817.

The product of its digits is 17920, while the sum is 33.

The square root of 81245247 is about 9013.6145358008. The cubic root of 81245247 is about 433.1111068966. Note that the first 4 decimals are identical.

The spelling of 81245247 in words is "eighty-one million, two hundred forty-five thousand, two hundred forty-seven".