663551 has 4 divisors (see below), whose sum is σ = 758352. Its totient is φ = 568752.

The previous prime is 663547. The next prime is 663557. The reversal of 663551 is 155366.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 663551 - 2² = 663547 is a prime.

It is a plaindrome in base 12.

It is a zygodrome in base 6.

It is a self number, because there is not a number n which added to its sum of digits gives 663551.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 663551.

It is not an unprimeable number, because it can be changed into a prime (663557) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47390 + ... + 47403.

It is an arithmetic number, because the mean of its divisors is an integer number (189588).

2⁶⁶³⁵⁵¹ is an apocalyptic number.

663551 is a deficient number, since it is larger than the sum of its proper divisors (94801).

663551 is an equidigital number, since it uses as much as digits as its factorization.

663551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94800.

The product of its digits is 2700, while the sum is 26.

The square root of 663551 is about 814.5863981187. The cubic root of 663551 is about 87.2217446403.

The spelling of 663551 in words is "six hundred sixty-three thousand, five hundred fifty-one".