21166670006021 has 4 divisors (see below), whose sum is σ = 21166847642892. Its totient is φ = 21166492369152.

The previous prime is 21166670005997. The next prime is 21166670006039. The reversal of 21166670006021 is 12060007666112.

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 10522796380996 + 10643873625025 = 3243886^2 + 3262495^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21166670006021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21166670006051) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 88639580 + ... + 88878053.

It is an arithmetic number, because the mean of its divisors is an integer number (5291711910723).

Almost surely, 2^{21166670006021} is an apocalyptic number.

It is an amenable number.

21166670006021 is a deficient number, since it is larger than the sum of its proper divisors (177636871).

21166670006021 is a wasteful number, since it uses less digits than its factorization.

21166670006021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 177636870.

The product of its (nonzero) digits is 36288, while the sum is 38.

The spelling of 21166670006021 in words is "twenty-one trillion, one hundred sixty-six billion, six hundred seventy million, six thousand, twenty-one".