2121662021761 has 2 divisors, whose sum is σ = 2121662021762. Its totient is φ = 2121662021760.

The previous prime is 2121662021737. The next prime is 2121662021783. The reversal of 2121662021761 is 1671202661212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1596290741136 + 525371280625 = 1263444^2 + 724825^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121662021761 - 2¹⁵ = 2121661988993 is a prime.

It is a super-2 number, since 2×2121662021761² (a number of 25 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 2121662021761.

It is not a weakly prime, because it can be changed into another prime (2121662021161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1060831010880 + 1060831010881.

It is an arithmetic number, because the mean of its divisors is an integer number (1060831010881).

Almost surely, 2^{2121662021761} is an apocalyptic number.

It is an amenable number.

2121662021761 is a deficient number, since it is larger than the sum of its proper divisors (1).

2121662021761 is an equidigital number, since it uses as much as digits as its factorization.

2121662021761 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24192, while the sum is 37.

Adding to 2121662021761 its reverse (1671202661212), we get a palindrome (3792864682973).

The spelling of 2121662021761 in words is "two trillion, one hundred twenty-one billion, six hundred sixty-two million, twenty-one thousand, seven hundred sixty-one".