661604378 has 16 divisors (see below), whose sum is σ = 1005086016. Its totient is φ = 326598720.

The previous prime is 661604369. The next prime is 661604389. The reversal of 661604378 is 873406166.

661604378 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53873 + ... + 65003.

It is an arithmetic number, because the mean of its divisors is an integer number (62817876).

Almost surely, 2^661604378 is an apocalyptic number.

661604378 is a deficient number, since it is larger than the sum of its proper divisors (343481638).

661604378 is a wasteful number, since it uses less digits than its factorization.

661604378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11509.

The product of its (nonzero) digits is 145152, while the sum is 41.

The square root of 661604378 is about 25721.6713687116. The cubic root of 661604378 is about 871.3636860021.

The spelling of 661604378 in words is "six hundred sixty-one million, six hundred four thousand, three hundred seventy-eight".