21171164642167 has 4 divisors (see below), whose sum is σ = 21171230276976. Its totient is φ = 21171099007360.

The previous prime is 21171164642087. The next prime is 21171164642183. The reversal of 21171164642167 is 76124646117112.

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

It is a cyclic number.

It is not a de Polignac number, because 21171164642167 - 2¹⁹ = 21171164117879 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21171164642167.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21171164645167) 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, 32331163 + ... + 32979484.

It is an arithmetic number, because the mean of its divisors is an integer number (5292807569244).

Almost surely, 2^{21171164642167} is an apocalyptic number.

21171164642167 is a deficient number, since it is larger than the sum of its proper divisors (65634809).

21171164642167 is an equidigital number, since it uses as much as digits as its factorization.

21171164642167 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65634808.

The product of its digits is 677376, while the sum is 49.

The spelling of 21171164642167 in words is "twenty-one trillion, one hundred seventy-one billion, one hundred sixty-four million, six hundred forty-two thousand, one hundred sixty-seven".