21166016310251 has 2 divisors, whose sum is σ = 21166016310252. Its totient is φ = 21166016310250.

The previous prime is 21166016310203. The next prime is 21166016310287. The reversal of 21166016310251 is 15201361066112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21166016310251 - 2³⁸ = 20891138403307 is a prime.

It is a super-2 number, since 2×21166016310251² (a number of 27 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (21166016310851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10583008155125 + 10583008155126.

It is an arithmetic number, because the mean of its divisors is an integer number (10583008155126).

Almost surely, 2^{21166016310251} is an apocalyptic number.

21166016310251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21166016310251 is an equidigital number, since it uses as much as digits as its factorization.

21166016310251 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 35.

Adding to 21166016310251 its reverse (15201361066112), we get a palindrome (36367377376363).

The spelling of 21166016310251 in words is "twenty-one trillion, one hundred sixty-six billion, sixteen million, three hundred ten thousand, two hundred fifty-one".