81145447 has 8 divisors (see below), whose sum is σ = 86298800. Its totient is φ = 76080384.

The previous prime is 81145417. The next prime is 81145457. The reversal of 81145447 is 74454118.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 81145447 - 2²³ = 72756839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81145417) 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, 20172 + ... + 23857.

It is an arithmetic number, because the mean of its divisors is an integer number (10787350).

Almost surely, 2^81145447 is an apocalyptic number.

81145447 is a deficient number, since it is larger than the sum of its proper divisors (5153353).

81145447 is a wasteful number, since it uses less digits than its factorization.

81145447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44145.

The product of its digits is 17920, while the sum is 34.

The square root of 81145447 is about 9008.0767647706. The cubic root of 81145447 is about 432.9336926238.

The spelling of 81145447 in words is "eighty-one million, one hundred forty-five thousand, four hundred forty-seven".