21000221100137 has 2 divisors, whose sum is σ = 21000221100138. Its totient is φ = 21000221100136.

The previous prime is 21000221099989. The next prime is 21000221100143. The reversal of 21000221100137 is 73100112200012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19919627585881 + 1080593514256 = 4463141^2 + 1039516^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000221100137 - 2¹⁰ = 21000221099113 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000221100167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500110550068 + 10500110550069.

It is an arithmetic number, because the mean of its divisors is an integer number (10500110550069).

Almost surely, 2^{21000221100137} is an apocalyptic number.

It is an amenable number.

21000221100137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000221100137 is an equidigital number, since it uses as much as digits as its factorization.

21000221100137 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 20.

Adding to 21000221100137 its reverse (73100112200012), we get a palindrome (94100333300149).

The spelling of 21000221100137 in words is "twenty-one trillion, two hundred twenty-one million, one hundred thousand, one hundred thirty-seven".