81753609 has 24 divisors (see below), whose sum is σ = 130237248. Its totient is φ = 45450720.

The previous prime is 81753593. The next prime is 81753611. The reversal of 81753609 is 90635718.

It is not a de Polignac number, because 81753609 - 2⁴ = 81753593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81753209) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2077 + ... + 12954.

It is an arithmetic number, because the mean of its divisors is an integer number (5426552).

Almost surely, 2^81753609 is an apocalyptic number.

It is an amenable number.

81753609 is a deficient number, since it is larger than the sum of its proper divisors (48483639).

81753609 is a wasteful number, since it uses less digits than its factorization.

81753609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15085 (or 15078 counting only the distinct ones).

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 81753609 is about 9041.7702359660. The cubic root of 81753609 is about 434.0125733437.

The spelling of 81753609 in words is "eighty-one million, seven hundred fifty-three thousand, six hundred nine".