81447912 has 192 divisors, whose sum is σ = 280949760. Its totient is φ = 20736000.

The previous prime is 81447887. The next prime is 81447913. The reversal of 81447912 is 21974418.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81447913) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 202912 + ... + 203312.

It is an arithmetic number, because the mean of its divisors is an integer number (1463280).

Almost surely, 2^81447912 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81447912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140474880).

81447912 is an abundant number, since it is smaller than the sum of its proper divisors (199501848).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81447912 is a wasteful number, since it uses less digits than its factorization.

81447912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 464 (or 457 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 81447912 is about 9024.8496940392. The cubic root of 81447912 is about 433.4709374960.

The spelling of 81447912 in words is "eighty-one million, four hundred forty-seven thousand, nine hundred twelve".