81353447 has 4 divisors (see below), whose sum is σ = 92975376. Its totient is φ = 69731520.

The previous prime is 81353431. The next prime is 81353473. The reversal of 81353447 is 74435318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74435318 = 2 ⋅37217659.

It is a cyclic number.

It is not a de Polignac number, because 81353447 - 2⁴ = 81353431 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 (81353407) 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, 5810954 + ... + 5810967.

It is an arithmetic number, because the mean of its divisors is an integer number (23243844).

Almost surely, 2^81353447 is an apocalyptic number.

81353447 is a deficient number, since it is larger than the sum of its proper divisors (11621929).

81353447 is a wasteful number, since it uses less digits than its factorization.

81353447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11621928.

The product of its digits is 40320, while the sum is 35.

The square root of 81353447 is about 9019.6145704792. The cubic root of 81353447 is about 433.3032897646.

The spelling of 81353447 in words is "eighty-one million, three hundred fifty-three thousand, four hundred forty-seven".