671305509 has 16 divisors (see below), whose sum is σ = 1136602240. Its totient is φ = 383603040.

The previous prime is 671305501. The next prime is 671305513. The reversal of 671305509 is 905503176.

It is a happy number.

671305509 is a `hidden beast` number, since 6 + 71 + 30 + 550 + 9 = 666.

It is not a de Polignac number, because 671305509 - 2³ = 671305501 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 (671305501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1775752 + ... + 1776129.

It is an arithmetic number, because the mean of its divisors is an integer number (71037640).

Almost surely, 2^671305509 is an apocalyptic number.

It is an amenable number.

671305509 is a deficient number, since it is larger than the sum of its proper divisors (465296731).

671305509 is a wasteful number, since it uses less digits than its factorization.

671305509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3551897 (or 3551891 counting only the distinct ones).

The product of its (nonzero) digits is 28350, while the sum is 36.

The square root of 671305509 is about 25909.5640449622. The cubic root of 671305509 is about 875.6019842269.

The spelling of 671305509 in words is "six hundred seventy-one million, three hundred five thousand, five hundred nine".