665729825 has 12 divisors (see below), whose sum is σ = 861397248. Its totient is φ = 509427600.

The previous prime is 665729791. The next prime is 665729861. The reversal of 665729825 is 528927566.

It is not a de Polignac number, because 665729825 - 2²⁴ = 648952609 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 578321 + ... + 579470.

It is an arithmetic number, because the mean of its divisors is an integer number (71783104).

Almost surely, 2^665729825 is an apocalyptic number.

It is an amenable number.

665729825 is a deficient number, since it is larger than the sum of its proper divisors (195667423).

665729825 is a wasteful number, since it uses less digits than its factorization.

665729825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1157824 (or 1157819 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 50.

The square root of 665729825 is about 25801.7407358496. The cubic root of 665729825 is about 873.1710696179.

The spelling of 665729825 in words is "six hundred sixty-five million, seven hundred twenty-nine thousand, eight hundred twenty-five".