20161993 has 2 divisors, whose sum is σ = 20161994. Its totient is φ = 20161992.

The previous prime is 20161991. The next prime is 20162027. The reversal of 20161993 is 39916102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14653584 + 5508409 = 3828^2 + 2347^2 .

It is a cyclic number.

It is not a de Polignac number, because 20161993 - 2¹ = 20161991 is a prime.

Together with 20161991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20161991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10080996 + 10080997.

It is an arithmetic number, because the mean of its divisors is an integer number (10080997).

Almost surely, 2^20161993 is an apocalyptic number.

It is an amenable number.

20161993 is a deficient number, since it is larger than the sum of its proper divisors (1).

20161993 is an equidigital number, since it uses as much as digits as its factorization.

20161993 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 31.

The square root of 20161993 is about 4490.2107968335. The cubic root of 20161993 is about 272.1726529640.

The spelling of 20161993 in words is "twenty million, one hundred sixty-one thousand, nine hundred ninety-three".