81409147 has 4 divisors (see below), whose sum is σ = 81490840. Its totient is φ = 81327456.

The previous prime is 81409117. The next prime is 81409187. The reversal of 81409147 is 74190418.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81409147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81409117) 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, 39333 + ... + 41350.

It is an arithmetic number, because the mean of its divisors is an integer number (20372710).

Almost surely, 2^81409147 is an apocalyptic number.

81409147 is a deficient number, since it is larger than the sum of its proper divisors (81693).

81409147 is a wasteful number, since it uses less digits than its factorization.

81409147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81692.

The product of its (nonzero) digits is 8064, while the sum is 34.

The square root of 81409147 is about 9022.7017572344. The cubic root of 81409147 is about 433.4021566558.

The spelling of 81409147 in words is "eighty-one million, four hundred nine thousand, one hundred forty-seven".