663604861 has 4 divisors (see below), whose sum is σ = 667079424. Its totient is φ = 660130300.

The previous prime is 663604841. The next prime is 663604867. The reversal of 663604861 is 168406366.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 663604861 - 2⁵ = 663604829 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663604867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1736995 + ... + 1737376.

It is an arithmetic number, because the mean of its divisors is an integer number (166769856).

Almost surely, 2^663604861 is an apocalyptic number.

It is an amenable number.

663604861 is a deficient number, since it is larger than the sum of its proper divisors (3474563).

663604861 is a wasteful number, since it uses less digits than its factorization.

663604861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3474562.

The product of its (nonzero) digits is 124416, while the sum is 40.

The square root of 663604861 is about 25760.5291288824. The cubic root of 663604861 is about 872.2410453091.

The spelling of 663604861 in words is "six hundred sixty-three million, six hundred four thousand, eight hundred sixty-one".