665601953 has 4 divisors (see below), whose sum is σ = 671822640. Its totient is φ = 659381268.

The previous prime is 665601929. The next prime is 665601967. The reversal of 665601953 is 359106566.

665601953 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 665601953 - 2¹² = 665597857 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 665601953.

It is not an unprimeable number, because it can be changed into a prime (665621953) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3110183 + ... + 3110396.

It is an arithmetic number, because the mean of its divisors is an integer number (167955660).

Almost surely, 2^665601953 is an apocalyptic number.

It is an amenable number.

665601953 is a deficient number, since it is larger than the sum of its proper divisors (6220687).

665601953 is a wasteful number, since it uses less digits than its factorization.

665601953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6220686.

The product of its (nonzero) digits is 145800, while the sum is 41.

The square root of 665601953 is about 25799.2626445021. The cubic root of 665601953 is about 873.1151604105.

The spelling of 665601953 in words is "six hundred sixty-five million, six hundred one thousand, nine hundred fifty-three".