663533993 has 2 divisors, whose sum is σ = 663533994. Its totient is φ = 663533992.

The previous prime is 663533971. The next prime is 663533999. The reversal of 663533993 is 399335366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 644550544 + 18983449 = 25388^2 + 4357^2 .

It is a cyclic number.

It is not a de Polignac number, because 663533993 - 2¹² = 663529897 is a prime.

It is a super-4 number, since 4×663533993⁴ (a number of 36 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (663533999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331766996 + 331766997.

It is an arithmetic number, because the mean of its divisors is an integer number (331766997).

Almost surely, 2^663533993 is an apocalyptic number.

It is an amenable number.

663533993 is a deficient number, since it is larger than the sum of its proper divisors (1).

663533993 is an equidigital number, since it uses as much as digits as its factorization.

663533993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1180980, while the sum is 47.

The square root of 663533993 is about 25759.1535769326. The cubic root of 663533993 is about 872.2099946128.

The spelling of 663533993 in words is "six hundred sixty-three million, five hundred thirty-three thousand, nine hundred ninety-three".