661520648 has 16 divisors (see below), whose sum is σ = 1250119680. Its totient is φ = 328155408.

The previous prime is 661520647. The next prime is 661520689. The reversal of 661520648 is 846025166.

It is not an unprimeable number, because it can be changed into a prime (661520647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 324536 + ... + 326567.

It is an arithmetic number, because the mean of its divisors is an integer number (78132480).

Almost surely, 2^661520648 is an apocalyptic number.

It is an amenable number.

661520648 is a deficient number, since it is larger than the sum of its proper divisors (588599032).

661520648 is a wasteful number, since it uses less digits than its factorization.

661520648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 651236 (or 651232 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 661520648 is about 25720.0437013626. The cubic root of 661520648 is about 871.3269256853.

The spelling of 661520648 in words is "six hundred sixty-one million, five hundred twenty thousand, six hundred forty-eight".