21000001221137 has 2 divisors, whose sum is σ = 21000001221138. Its totient is φ = 21000001221136.

The previous prime is 21000001221079. The next prime is 21000001221151. The reversal of 21000001221137 is 73112210000012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14288709961681 + 6711291259456 = 3780041^2 + 2590616^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000001221137 - 2²⁶ = 20999934112273 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000001221167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500000610568 + 10500000610569.

It is an arithmetic number, because the mean of its divisors is an integer number (10500000610569).

Almost surely, 2^{21000001221137} is an apocalyptic number.

It is an amenable number.

21000001221137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000001221137 is an equidigital number, since it uses as much as digits as its factorization.

21000001221137 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 21000001221137 its reverse (73112210000012), we get a palindrome (94112211221149).

The spelling of 21000001221137 in words is "twenty-one trillion, one million, two hundred twenty-one thousand, one hundred thirty-seven".