21551235301237 has 2 divisors, whose sum is σ = 21551235301238. Its totient is φ = 21551235301236.

The previous prime is 21551235301163. The next prime is 21551235301279. The reversal of 21551235301237 is 73210353215512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20613425120401 + 937810180836 = 4540201^2 + 968406^2 .

It is a cyclic number.

It is not a de Polignac number, because 21551235301237 - 2¹⁵ = 21551235268469 is a prime.

It is a super-2 number, since 2×21551235301237² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21551235301237.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21551232301237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10775617650618 + 10775617650619.

It is an arithmetic number, because the mean of its divisors is an integer number (10775617650619).

Almost surely, 2^{21551235301237} is an apocalyptic number.

It is an amenable number.

21551235301237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21551235301237 is an equidigital number, since it uses as much as digits as its factorization.

21551235301237 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 189000, while the sum is 40.

Adding to 21551235301237 its reverse (73210353215512), we get a palindrome (94761588516749).

The spelling of 21551235301237 in words is "twenty-one trillion, five hundred fifty-one billion, two hundred thirty-five million, three hundred one thousand, two hundred thirty-seven".