81365009 has 8 divisors (see below), whose sum is σ = 93983328. Its totient is φ = 69616960.

The previous prime is 81364999. The next prime is 81365029. The reversal of 81365009 is 90056318.

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 81365009 - 2²⁰ = 80316433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81365029) 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, 217367 + ... + 217740.

It is an arithmetic number, because the mean of its divisors is an integer number (11747916).

Almost surely, 2^81365009 is an apocalyptic number.

It is an amenable number.

81365009 is a deficient number, since it is larger than the sum of its proper divisors (12618319).

81365009 is a wasteful number, since it uses less digits than its factorization.

81365009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 435135.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 81365009 is about 9020.2554841867. The cubic root of 81365009 is about 433.3238158988.

The spelling of 81365009 in words is "eighty-one million, three hundred sixty-five thousand, nine".