661911604 has 12 divisors (see below), whose sum is σ = 1158539200. Its totient is φ = 330900408.

The previous prime is 661911589. The next prime is 661911617. The reversal of 661911604 is 406119166.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 661911604.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 25387 + ... + 44365.

Almost surely, 2^661911604 is an apocalyptic number.

It is an amenable number.

661911604 is a deficient number, since it is larger than the sum of its proper divisors (496627596).

661911604 is a wasteful number, since it uses less digits than its factorization.

661911604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27702 (or 27700 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 661911604 is about 25727.6427991373. The cubic root of 661911604 is about 871.4985420992.

The spelling of 661911604 in words is "six hundred sixty-one million, nine hundred eleven thousand, six hundred four".