666825403121 has 4 divisors (see below), whose sum is σ = 706050426852. Its totient is φ = 627600379392.

The previous prime is 666825403103. The next prime is 666825403157. The reversal of 666825403121 is 121304528666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 229158477025 + 437666926096 = 478705^2 + 661564^2 .

It is not a de Polignac number, because 666825403121 - 2¹⁸ = 666825140977 is a prime.

It is a super-2 number, since 2×666825403121² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666825403171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19612511840 + ... + 19612511873.

It is an arithmetic number, because the mean of its divisors is an integer number (176512606713).

Almost surely, 2^666825403121 is an apocalyptic number.

It is an amenable number.

666825403121 is a deficient number, since it is larger than the sum of its proper divisors (39225023731).

666825403121 is a wasteful number, since it uses less digits than its factorization.

666825403121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39225023730.

The product of its (nonzero) digits is 414720, while the sum is 44.

The spelling of 666825403121 in words is "six hundred sixty-six billion, eight hundred twenty-five million, four hundred three thousand, one hundred twenty-one".