663031679621 has 4 divisors (see below), whose sum is σ = 679203184044. Its totient is φ = 646860175200.

The previous prime is 663031679603. The next prime is 663031679657. The reversal of 663031679621 is 126976130366.

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 8890415521 + 654141264100 = 94289^2 + 808790^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-663031679621 is a prime.

It is a super-2 number, since 2×663031679621² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 663031679621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663033679621) 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, 8085752150 + ... + 8085752231.

It is an arithmetic number, because the mean of its divisors is an integer number (169800796011).

Almost surely, 2^663031679621 is an apocalyptic number.

It is an amenable number.

663031679621 is a deficient number, since it is larger than the sum of its proper divisors (16171504423).

663031679621 is a wasteful number, since it uses less digits than its factorization.

663031679621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16171504422.

The product of its (nonzero) digits is 1469664, while the sum is 50.

The spelling of 663031679621 in words is "six hundred sixty-three billion, thirty-one million, six hundred seventy-nine thousand, six hundred twenty-one".