660364821 has 24 divisors (see below), whose sum is σ = 992436224. Its totient is φ = 422664480.

The previous prime is 660364811. The next prime is 660364853. The reversal of 660364821 is 128463066.

660364821 is a `hidden beast` number, since 6 + 6 + 0 + 3 + 648 + 2 + 1 = 666.

It is not a de Polignac number, because 660364821 - 2⁷ = 660364693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660364811) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26115 + ... + 44751.

Almost surely, 2^660364821 is an apocalyptic number.

It is an amenable number.

660364821 is a deficient number, since it is larger than the sum of its proper divisors (332071403).

660364821 is a wasteful number, since it uses less digits than its factorization.

660364821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18801 (or 18798 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The square root of 660364821 is about 25697.5644954926. The cubic root of 660364821 is about 870.8191610849.

The spelling of 660364821 in words is "six hundred sixty million, three hundred sixty-four thousand, eight hundred twenty-one".