21221210137 has 2 divisors, whose sum is σ = 21221210138. Its totient is φ = 21221210136.

The previous prime is 21221210119. The next prime is 21221210147. The reversal of 21221210137 is 73101212212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20903087241 + 318122896 = 144579^2 + 17836^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21221210137 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221210147) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610605068 + 10610605069.

It is an arithmetic number, because the mean of its divisors is an integer number (10610605069).

Almost surely, 2^21221210137 is an apocalyptic number.

It is an amenable number.

21221210137 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221210137 is an equidigital number, since it uses as much as digits as its factorization.

21221210137 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 22.

Adding to 21221210137 its reverse (73101212212), we get a palindrome (94322422349).

The spelling of 21221210137 in words is "twenty-one billion, two hundred twenty-one million, two hundred ten thousand, one hundred thirty-seven".