66829127921 has 2 divisors, whose sum is σ = 66829127922. Its totient is φ = 66829127920.

The previous prime is 66829127909. The next prime is 66829127977. The reversal of 66829127921 is 12972192866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65359479025 + 1469648896 = 255655^2 + 38336^2 .

It is a cyclic number.

It is not a de Polignac number, because 66829127921 - 2¹⁴ = 66829111537 is a prime.

It is a super-2 number, since 2×66829127921² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (66829120921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33414563960 + 33414563961.

It is an arithmetic number, because the mean of its divisors is an integer number (33414563961).

Almost surely, 2^66829127921 is an apocalyptic number.

It is an amenable number.

66829127921 is a deficient number, since it is larger than the sum of its proper divisors (1).

66829127921 is an equidigital number, since it uses as much as digits as its factorization.

66829127921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 53.

The spelling of 66829127921 in words is "sixty-six billion, eight hundred twenty-nine million, one hundred twenty-seven thousand, nine hundred twenty-one".