2121221537 has 2 divisors, whose sum is σ = 2121221538. Its totient is φ = 2121221536.

The previous prime is 2121221477. The next prime is 2121221539. The reversal of 2121221537 is 7351221212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2112689296 + 8532241 = 45964^2 + 2921^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121221537 - 2⁸ = 2121221281 is a prime.

Together with 2121221539, 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 (2121221539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060610768 + 1060610769.

It is an arithmetic number, because the mean of its divisors is an integer number (1060610769).

Almost surely, 2^2121221537 is an apocalyptic number.

It is an amenable number.

2121221537 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121221537 is an equidigital number, since it uses as much as digits as its factorization.

2121221537 is an evil number, because the sum of its binary digits is even.

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

The square root of 2121221537 is about 46056.7208667747. The cubic root of 2121221537 is about 1284.8783438451.

Adding to 2121221537 its reverse (7351221212), we get a palindrome (9472442749).

The spelling of 2121221537 in words is "two billion, one hundred twenty-one million, two hundred twenty-one thousand, five hundred thirty-seven".