81735809 has 8 divisors (see below), whose sum is σ = 84480000. Its totient is φ = 78998400.

The previous prime is 81735793. The next prime is 81735811. The reversal of 81735809 is 90853718.

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 81735809 - 2⁴ = 81735793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81735889) 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, 37664 + ... + 39774.

It is an arithmetic number, because the mean of its divisors is an integer number (10560000).

Almost surely, 2^81735809 is an apocalyptic number.

It is an amenable number.

81735809 is a deficient number, since it is larger than the sum of its proper divisors (2744191).

81735809 is a wasteful number, since it uses less digits than its factorization.

81735809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3391.

The product of its (nonzero) digits is 60480, while the sum is 41.

The square root of 81735809 is about 9040.7858618596. The cubic root of 81735809 is about 433.9810722489.

The spelling of 81735809 in words is "eighty-one million, seven hundred thirty-five thousand, eight hundred nine".