993163921 has 2 divisors, whose sum is σ = 993163922. Its totient is φ = 993163920.

The previous prime is 993163859. The next prime is 993163931. The reversal of 993163921 is 129361399.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 778131025 + 215032896 = 27895^2 + 14664^2 .

It is an emirp because it is prime and its reverse (129361399) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 993163921 - 2¹⁹ = 992639633 is a prime.

It is not a weakly prime, because it can be changed into another prime (993163931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 496581960 + 496581961.

It is an arithmetic number, because the mean of its divisors is an integer number (496581961).

Almost surely, 2^993163921 is an apocalyptic number.

It is an amenable number.

993163921 is a deficient number, since it is larger than the sum of its proper divisors (1).

993163921 is an equidigital number, since it uses as much as digits as its factorization.

993163921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 78732, while the sum is 43.

The square root of 993163921 is about 31514.5033436988. The cubic root of 993163921 is about 997.7160947479.

The spelling of 993163921 in words is "nine hundred ninety-three million, one hundred sixty-three thousand, nine hundred twenty-one".