663555261 has 8 divisors (see below), whose sum is σ = 887291424. Its totient is φ = 441094640.

The previous prime is 663555247. The next prime is 663555289. The reversal of 663555261 is 162555366.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 663555261 - 2⁵ = 663555229 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663555161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 317670 + ... + 319751.

It is an arithmetic number, because the mean of its divisors is an integer number (110911428).

Almost surely, 2^663555261 is an apocalyptic number.

It is an amenable number.

663555261 is a deficient number, since it is larger than the sum of its proper divisors (223736163).

663555261 is a wasteful number, since it uses less digits than its factorization.

663555261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 637771.

The product of its digits is 162000, while the sum is 39.

The square root of 663555261 is about 25759.5663977482. The cubic root of 663555261 is about 872.2193133838.

The spelling of 663555261 in words is "six hundred sixty-three million, five hundred fifty-five thousand, two hundred sixty-one".