661220204 has 24 divisors (see below), whose sum is σ = 1209600000. Its totient is φ = 315890640.

The previous prime is 661220149. The next prime is 661220207. The reversal of 661220204 is 402022166.

It is a self number, because there is not a number n which added to its sum of digits gives 661220204.

It is not an unprimeable number, because it can be changed into a prime (661220207) 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 7 ways as a sum of consecutive naturals, for example, 23954 + ... + 43545.

It is an arithmetic number, because the mean of its divisors is an integer number (50400000).

Almost surely, 2^661220204 is an apocalyptic number.

It is an amenable number.

661220204 is a deficient number, since it is larger than the sum of its proper divisors (548379796).

661220204 is a wasteful number, since it uses less digits than its factorization.

661220204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67613 (or 67611 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 661220204 is about 25714.2023792300. The cubic root of 661220204 is about 871.1949950145.

The spelling of 661220204 in words is "six hundred sixty-one million, two hundred twenty thousand, two hundred four".