663832532617921 has 4 divisors (see below), whose sum is σ = 663833044465492. Its totient is φ = 663832020770352.

The previous prime is 663832532617873. The next prime is 663832532617927. The reversal of 663832532617921 is 129716235238366.

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 661314661849521 + 2517870768400 = 25716039^2 + 1586780^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-663832532617921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (663832532617927) 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, 253973430 + ... + 256573903.

It is an arithmetic number, because the mean of its divisors is an integer number (165958261116373).

Almost surely, 2^{663832532617921} is an apocalyptic number.

It is an amenable number.

663832532617921 is a deficient number, since it is larger than the sum of its proper divisors (511847571).

663832532617921 is a wasteful number, since it uses less digits than its factorization.

663832532617921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511847570.

The product of its digits is 117573120, while the sum is 64.

The spelling of 663832532617921 in words is "six hundred sixty-three trillion, eight hundred thirty-two billion, five hundred thirty-two million, six hundred seventeen thousand, nine hundred twenty-one".