663597421 has 2 divisors, whose sum is σ = 663597422. Its totient is φ = 663597420.

The previous prime is 663597419. The next prime is 663597427. The reversal of 663597421 is 124795366.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 652240521 + 11356900 = 25539^2 + 3370^2 .

It is a cyclic number.

It is not a de Polignac number, because 663597421 - 2¹ = 663597419 is a prime.

Together with 663597419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (663597427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331798710 + 331798711.

It is an arithmetic number, because the mean of its divisors is an integer number (331798711).

Almost surely, 2^663597421 is an apocalyptic number.

It is an amenable number.

663597421 is a deficient number, since it is larger than the sum of its proper divisors (1).

663597421 is an equidigital number, since it uses as much as digits as its factorization.

663597421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 272160, while the sum is 43.

The square root of 663597421 is about 25760.3847215060. The cubic root of 663597421 is about 872.2377855894.

The spelling of 663597421 in words is "six hundred sixty-three million, five hundred ninety-seven thousand, four hundred twenty-one".