663481645 has 4 divisors (see below), whose sum is σ = 796177980. Its totient is φ = 530785312.

The previous prime is 663481631. The next prime is 663481673. The reversal of 663481645 is 546184366.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 191462569 + 472019076 = 13837^2 + 21726^2 .

It is a cyclic number.

It is not a de Polignac number, because 663481645 - 2¹⁷ = 663350573 is a prime.

It is a super-3 number, since 3×663481645³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66348160 + ... + 66348169.

It is an arithmetic number, because the mean of its divisors is an integer number (199044495).

Almost surely, 2^663481645 is an apocalyptic number.

It is an amenable number.

663481645 is a deficient number, since it is larger than the sum of its proper divisors (132696335).

663481645 is a wasteful number, since it uses less digits than its factorization.

663481645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132696334.

The product of its digits is 414720, while the sum is 43.

The square root of 663481645 is about 25758.1374520752. The cubic root of 663481645 is about 872.1870570040.

The spelling of 663481645 in words is "six hundred sixty-three million, four hundred eighty-one thousand, six hundred forty-five".