993518381 has 2 divisors, whose sum is σ = 993518382. Its totient is φ = 993518380.

The previous prime is 993518363. The next prime is 993518387. The reversal of 993518381 is 183815399.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 641355625 + 352162756 = 25325^2 + 18766^2 .

It is a cyclic number.

It is not a de Polignac number, because 993518381 - 2¹⁸ = 993256237 is a prime.

It is a super-2 number, since 2×993518381² = 1974157546769722322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (993518387) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 496759190 + 496759191.

It is an arithmetic number, because the mean of its divisors is an integer number (496759191).

Almost surely, 2^993518381 is an apocalyptic number.

It is an amenable number.

993518381 is a deficient number, since it is larger than the sum of its proper divisors (1).

993518381 is an equidigital number, since it uses as much as digits as its factorization.

993518381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 233280, while the sum is 47.

The square root of 993518381 is about 31520.1266019031. The cubic root of 993518381 is about 997.8347755200.

The spelling of 993518381 in words is "nine hundred ninety-three million, five hundred eighteen thousand, three hundred eighty-one".