2121532637657 has 2 divisors, whose sum is σ = 2121532637658. Its totient is φ = 2121532637656.

The previous prime is 2121532637617. The next prime is 2121532637681. The reversal of 2121532637657 is 7567362351212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1831247671696 + 290284965961 = 1353236^2 + 538781^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121532637657 - 2²⁴ = 2121515860441 is a prime.

It is not a weakly prime, because it can be changed into another prime (2121532637617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060766318828 + 1060766318829.

It is an arithmetic number, because the mean of its divisors is an integer number (1060766318829).

Almost surely, 2^{2121532637657} is an apocalyptic number.

It is an amenable number.

2121532637657 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121532637657 is an equidigital number, since it uses as much as digits as its factorization.

2121532637657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3175200, while the sum is 50.

Adding to 2121532637657 its reverse (7567362351212), we get a palindrome (9688894988869).

The spelling of 2121532637657 in words is "two trillion, one hundred twenty-one billion, five hundred thirty-two million, six hundred thirty-seven thousand, six hundred fifty-seven".