2121501705221 has 2 divisors, whose sum is σ = 2121501705222. Its totient is φ = 2121501705220.

The previous prime is 2121501705203. The next prime is 2121501705229. The reversal of 2121501705221 is 1225071051212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1132332220321 + 989169484900 = 1064111^2 + 994570^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121501705221 - 2¹⁸ = 2121501443077 is a prime.

It is a super-2 number, since 2×2121501705221² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2121501705229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060750852610 + 1060750852611.

It is an arithmetic number, because the mean of its divisors is an integer number (1060750852611).

Almost surely, 2^{2121501705221} is an apocalyptic number.

It is an amenable number.

2121501705221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121501705221 is an equidigital number, since it uses as much as digits as its factorization.

2121501705221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2800, while the sum is 29.

Adding to 2121501705221 its reverse (1225071051212), we get a palindrome (3346572756433).

The spelling of 2121501705221 in words is "two trillion, one hundred twenty-one billion, five hundred one million, seven hundred five thousand, two hundred twenty-one".