661953201 has 24 divisors (see below), whose sum is σ = 1105683264. Its totient is φ = 349161120.

The previous prime is 661953169. The next prime is 661953251. The reversal of 661953201 is 102359166.

It is a happy number.

It is not a de Polignac number, because 661953201 - 2⁵ = 661953169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661953251) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 171285 + ... + 175106.

It is an arithmetic number, because the mean of its divisors is an integer number (46070136).

Almost surely, 2^661953201 is an apocalyptic number.

It is an amenable number.

661953201 is a deficient number, since it is larger than the sum of its proper divisors (443730063).

661953201 is a wasteful number, since it uses less digits than its factorization.

661953201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346421 (or 346414 counting only the distinct ones).

The product of its (nonzero) digits is 9720, while the sum is 33.

The square root of 661953201 is about 25728.4511970698. The cubic root of 661953201 is about 871.5167977924.

It can be divided in two parts, 66195 and 3201, that added together give a palindrome (69396).

The spelling of 661953201 in words is "six hundred sixty-one million, nine hundred fifty-three thousand, two hundred one".