663891841 has 4 divisors (see below), whose sum is σ = 664432384. Its totient is φ = 663351300.

The previous prime is 663891829. The next prime is 663891869. The reversal of 663891841 is 148198366.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 663891841 - 2⁹ = 663891329 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 663891791 and 663891800.

It is not an unprimeable number, because it can be changed into a prime (663891821) 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, 268425 + ... + 270886.

It is an arithmetic number, because the mean of its divisors is an integer number (166108096).

Almost surely, 2^663891841 is an apocalyptic number.

It is an amenable number.

663891841 is a deficient number, since it is larger than the sum of its proper divisors (540543).

663891841 is a wasteful number, since it uses less digits than its factorization.

663891841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540542.

The product of its digits is 248832, while the sum is 46.

The square root of 663891841 is about 25766.0986763615. The cubic root of 663891841 is about 872.3667625218.

The spelling of 663891841 in words is "six hundred sixty-three million, eight hundred ninety-one thousand, eight hundred forty-one".