663633409 has 2 divisors, whose sum is σ = 663633410. Its totient is φ = 663633408.

The previous prime is 663633407. The next prime is 663633413. The reversal of 663633409 is 904336366.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 593994384 + 69639025 = 24372^2 + 8345^2 .

It is a cyclic number.

It is not a de Polignac number, because 663633409 - 2¹ = 663633407 is a prime.

It is a super-2 number, since 2×663633409² = 880818603081922562, which contains 22 as substring.

Together with 663633407, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (663633407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331816704 + 331816705.

It is an arithmetic number, because the mean of its divisors is an integer number (331816705).

Almost surely, 2^663633409 is an apocalyptic number.

It is an amenable number.

663633409 is a deficient number, since it is larger than the sum of its proper divisors (1).

663633409 is an equidigital number, since it uses as much as digits as its factorization.

663633409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 209952, while the sum is 40.

The square root of 663633409 is about 25761.0832264484. The cubic root of 663633409 is about 872.2535529432.

The spelling of 663633409 in words is "six hundred sixty-three million, six hundred thirty-three thousand, four hundred nine".