1993512821 has 2 divisors, whose sum is σ = 1993512822. Its totient is φ = 1993512820.

The previous prime is 1993512767. The next prime is 1993512839. The reversal of 1993512821 is 1282153991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1865030596 + 128482225 = 43186^2 + 11335^2 .

It is a cyclic number.

It is not a de Polignac number, because 1993512821 - 2³⁰ = 919770997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1993512221) 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, 996756410 + 996756411.

It is an arithmetic number, because the mean of its divisors is an integer number (996756411).

Almost surely, 2^1993512821 is an apocalyptic number.

It is an amenable number.

1993512821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1993512821 is an equidigital number, since it uses as much as digits as its factorization.

1993512821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 41.

The square root of 1993512821 is about 44648.7717748204. The cubic root of 1993512821 is about 1258.5573521758.

The spelling of 1993512821 in words is "one billion, nine hundred ninety-three million, five hundred twelve thousand, eight hundred twenty-one".