21201021137 has 2 divisors, whose sum is σ = 21201021138. Its totient is φ = 21201021136.

The previous prime is 21201021133. The next prime is 21201021139. The reversal of 21201021137 is 73112010212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21157447936 + 43573201 = 145456^2 + 6601^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201021137 - 2² = 21201021133 is a prime.

Together with 21201021139, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21201021133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600510568 + 10600510569.

It is an arithmetic number, because the mean of its divisors is an integer number (10600510569).

Almost surely, 2^21201021137 is an apocalyptic number.

It is an amenable number.

21201021137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201021137 is an equidigital number, since it uses as much as digits as its factorization.

21201021137 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 21201021137 its reverse (73112010212), we get a palindrome (94313031349).

The spelling of 21201021137 in words is "twenty-one billion, two hundred one million, twenty-one thousand, one hundred thirty-seven".