21210166679 has 4 divisors (see below), whose sum is σ = 22841717976. Its totient is φ = 19578615384.

The previous prime is 21210166673. The next prime is 21210166693. The reversal of 21210166679 is 97666101212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21210166679 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 (21210166673) 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, 815775629 + ... + 815775654.

It is an arithmetic number, because the mean of its divisors is an integer number (5710429494).

Almost surely, 2^21210166679 is an apocalyptic number.

21210166679 is a deficient number, since it is larger than the sum of its proper divisors (1631551297).

21210166679 is a wasteful number, since it uses less digits than its factorization.

21210166679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1631551296.

The product of its (nonzero) digits is 54432, while the sum is 41.

The spelling of 21210166679 in words is "twenty-one billion, two hundred ten million, one hundred sixty-six thousand, six hundred seventy-nine".