664081509 has 16 divisors (see below), whose sum is σ = 1089775232. Its totient is φ = 350284608.

The previous prime is 664081499. The next prime is 664081529. The reversal of 664081509 is 905180466.

It is not a de Polignac number, because 664081509 - 2¹¹ = 664079461 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664081529) 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, 1215994 + ... + 1216539.

It is an arithmetic number, because the mean of its divisors is an integer number (68110952).

Almost surely, 2^664081509 is an apocalyptic number.

It is an amenable number.

664081509 is a deficient number, since it is larger than the sum of its proper divisors (425693723).

664081509 is a wasteful number, since it uses less digits than its factorization.

664081509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2432556.

The product of its (nonzero) digits is 51840, while the sum is 39.

The square root of 664081509 is about 25769.7789862467. The cubic root of 664081509 is about 872.4498304226.

The spelling of 664081509 in words is "six hundred sixty-four million, eighty-one thousand, five hundred nine".