20011221137 has 2 divisors, whose sum is σ = 20011221138. Its totient is φ = 20011221136.

The previous prime is 20011221127. The next prime is 20011221149. The reversal of 20011221137 is 73112211002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18046160896 + 1965060241 = 134336^2 + 44329^2 .

It is a cyclic number.

It is not a de Polignac number, because 20011221137 - 2¹⁰ = 20011220113 is a prime.

It is not a weakly prime, because it can be changed into another prime (20011221107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005610568 + 10005610569.

It is an arithmetic number, because the mean of its divisors is an integer number (10005610569).

Almost surely, 2^20011221137 is an apocalyptic number.

It is an amenable number.

20011221137 is a deficient number, since it is larger than the sum of its proper divisors (1).

20011221137 is an equidigital number, since it uses as much as digits as its factorization.

20011221137 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 20011221137 its reverse (73112211002), we get a palindrome (93123432139).

The spelling of 20011221137 in words is "twenty billion, eleven million, two hundred twenty-one thousand, one hundred thirty-seven".