665571953 has 16 divisors (see below), whose sum is σ = 741657600. Its totient is φ = 594834240.

The previous prime is 665571943. The next prime is 665571989. The reversal of 665571953 is 359175566.

It is a cyclic number.

It is not a de Polignac number, because 665571953 - 2¹² = 665567857 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 665571898 and 665571907.

It is not an unprimeable number, because it can be changed into a prime (665571923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4583 + ... + 36771.

It is an arithmetic number, because the mean of its divisors is an integer number (46353600).

Almost surely, 2^665571953 is an apocalyptic number.

It is an amenable number.

665571953 is a deficient number, since it is larger than the sum of its proper divisors (76085647).

665571953 is a wasteful number, since it uses less digits than its factorization.

665571953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32272.

The product of its digits is 850500, while the sum is 47.

The square root of 665571953 is about 25798.6812259852. The cubic root of 665571953 is about 873.1020425362.

The spelling of 665571953 in words is "six hundred sixty-five million, five hundred seventy-one thousand, nine hundred fifty-three".