660661838 has 4 divisors (see below), whose sum is σ = 990992760. Its totient is φ = 330330918.

The previous prime is 660661831. The next prime is 660661843. The reversal of 660661838 is 838166066.

660661838 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 838166066 = 2 ⋅419083033.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660661831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165165458 + ... + 165165461.

It is an arithmetic number, because the mean of its divisors is an integer number (247748190).

Almost surely, 2^660661838 is an apocalyptic number.

660661838 is a deficient number, since it is larger than the sum of its proper divisors (330330922).

660661838 is a wasteful number, since it uses less digits than its factorization.

660661838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330330921.

The product of its (nonzero) digits is 248832, while the sum is 44.

The square root of 660661838 is about 25703.3429343344. The cubic root of 660661838 is about 870.9496996994.

The spelling of 660661838 in words is "six hundred sixty million, six hundred sixty-one thousand, eight hundred thirty-eight".