21215201237 has 2 divisors, whose sum is σ = 21215201238. Its totient is φ = 21215201236.

The previous prime is 21215201209. The next prime is 21215201251. The reversal of 21215201237 is 73210251212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21094948081 + 120253156 = 145241^2 + 10966^2 .

It is a cyclic number.

It is not a de Polignac number, because 21215201237 - 2¹⁶ = 21215135701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21215201207) 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, 10607600618 + 10607600619.

It is an arithmetic number, because the mean of its divisors is an integer number (10607600619).

Almost surely, 2^21215201237 is an apocalyptic number.

It is an amenable number.

21215201237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21215201237 is an equidigital number, since it uses as much as digits as its factorization.

21215201237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1680, while the sum is 26.

Adding to 21215201237 its reverse (73210251212), we get a palindrome (94425452449).

The spelling of 21215201237 in words is "twenty-one billion, two hundred fifteen million, two hundred one thousand, two hundred thirty-seven".