2691116916221 has 2 divisors, whose sum is σ = 2691116916222. Its totient is φ = 2691116916220.

The previous prime is 2691116916209. The next prime is 2691116916239. The reversal of 2691116916221 is 1226196111962.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2688976836100 + 2140080121 = 1639810^2 + 46261^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2691116916221 is a prime.

It is a super-2 number, since 2×2691116916221² (a number of 26 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2691116916281) 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, 1345558458110 + 1345558458111.

It is an arithmetic number, because the mean of its divisors is an integer number (1345558458111).

Almost surely, 2^{2691116916221} is an apocalyptic number.

It is an amenable number.

2691116916221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2691116916221 is an equidigital number, since it uses as much as digits as its factorization.

2691116916221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 47.

The spelling of 2691116916221 in words is "two trillion, six hundred ninety-one billion, one hundred sixteen million, nine hundred sixteen thousand, two hundred twenty-one".