10521666121 has 2 divisors, whose sum is σ = 10521666122. Its totient is φ = 10521666120.

The previous prime is 10521666107. The next prime is 10521666167. The reversal of 10521666121 is 12166612501.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10437687225 + 83978896 = 102165^2 + 9164^2 .

It is a cyclic number.

It is not a de Polignac number, because 10521666121 - 2¹⁷ = 10521535049 is a prime.

It is a super-2 number, since 2×10521666121² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (10521666721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5260833060 + 5260833061.

It is an arithmetic number, because the mean of its divisors is an integer number (5260833061).

Almost surely, 2^10521666121 is an apocalyptic number.

It is an amenable number.

10521666121 is a deficient number, since it is larger than the sum of its proper divisors (1).

10521666121 is an equidigital number, since it uses as much as digits as its factorization.

10521666121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 31.

The spelling of 10521666121 in words is "ten billion, five hundred twenty-one million, six hundred sixty-six thousand, one hundred twenty-one".