663720973 has 2 divisors, whose sum is σ = 663720974. Its totient is φ = 663720972.

The previous prime is 663720917. The next prime is 663720983. The reversal of 663720973 is 379027366.

663720973 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 532778724 + 130942249 = 23082^2 + 11443^2 .

It is a cyclic number.

It is not a de Polignac number, because 663720973 - 2²¹ = 661623821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (663720983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331860486 + 331860487.

It is an arithmetic number, because the mean of its divisors is an integer number (331860487).

Almost surely, 2^663720973 is an apocalyptic number.

It is an amenable number.

663720973 is a deficient number, since it is larger than the sum of its proper divisors (1).

663720973 is an equidigital number, since it uses as much as digits as its factorization.

663720973 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 285768, while the sum is 43.

The square root of 663720973 is about 25762.7827107244. The cubic root of 663720973 is about 872.2919148109.

The spelling of 663720973 in words is "six hundred sixty-three million, seven hundred twenty thousand, nine hundred seventy-three".