2166071210621 has 2 divisors, whose sum is σ = 2166071210622. Its totient is φ = 2166071210620.

The previous prime is 2166071210603. The next prime is 2166071210623. The reversal of 2166071210621 is 1260121706612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2086089148900 + 79982061721 = 1444330^2 + 282811^2 .

It is a cyclic number.

It is not a de Polignac number, because 2166071210621 - 2¹⁴ = 2166071194237 is a prime.

It is a super-2 number, since 2×2166071210621² (a number of 25 digits) contains 22 as substring.

Together with 2166071210623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2166071210623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1083035605310 + 1083035605311.

It is an arithmetic number, because the mean of its divisors is an integer number (1083035605311).

Almost surely, 2^{2166071210621} is an apocalyptic number.

It is an amenable number.

2166071210621 is a deficient number, since it is larger than the sum of its proper divisors (1).

2166071210621 is an equidigital number, since it uses as much as digits as its factorization.

2166071210621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 35.

The spelling of 2166071210621 in words is "two trillion, one hundred sixty-six billion, seventy-one million, two hundred ten thousand, six hundred twenty-one".