20001020221993 has 2 divisors, whose sum is σ = 20001020221994. Its totient is φ = 20001020221992.

The previous prime is 20001020221967. The next prime is 20001020222021. The reversal of 20001020221993 is 39912202010002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17719494559209 + 2281525662784 = 4209453^2 + 1510472^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20001020221993 is a prime.

It is not a weakly prime, because it can be changed into another prime (20001020221393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10000510110996 + 10000510110997.

It is an arithmetic number, because the mean of its divisors is an integer number (10000510110997).

Almost surely, 2^{20001020221993} is an apocalyptic number.

It is an amenable number.

20001020221993 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001020221993 is an equidigital number, since it uses as much as digits as its factorization.

20001020221993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

Adding to 20001020221993 its reverse (39912202010002), we get a palindrome (59913222231995).

The spelling of 20001020221993 in words is "twenty trillion, one billion, twenty million, two hundred twenty-one thousand, nine hundred ninety-three".