20001221137 has 2 divisors, whose sum is σ = 20001221138. Its totient is φ = 20001221136.

The previous prime is 20001221083. The next prime is 20001221147. The reversal of 20001221137 is 73112210002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17988442641 + 2012778496 = 134121^2 + 44864^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001221137 - 2¹¹ = 20001219089 is a prime.

It is not a weakly prime, because it can be changed into another prime (20001221147) 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, 10000610568 + 10000610569.

It is an arithmetic number, because the mean of its divisors is an integer number (10000610569).

Almost surely, 2^20001221137 is an apocalyptic number.

It is an amenable number.

20001221137 is a deficient number, since it is larger than the sum of its proper divisors (1).

20001221137 is an equidigital number, since it uses as much as digits as its factorization.

20001221137 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 19.

Adding to 20001221137 its reverse (73112210002), we get a palindrome (93113431139).

The spelling of 20001221137 in words is "twenty billion, one million, two hundred twenty-one thousand, one hundred thirty-seven".