21146541626165 has 4 divisors (see below), whose sum is σ = 25375849951404. Its totient is φ = 16917233300928.

The previous prime is 21146541626141. The next prime is 21146541626179. The reversal of 21146541626165 is 56162614564112.

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 16823631162244 + 4322910463921 = 4101662^2 + 2079161^2 .

It is a cyclic number.

It is not a de Polignac number, because 21146541626165 - 2⁴² = 16748495115061 is a prime.

It is a super-2 number, since 2×21146541626165² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2114654162612 + ... + 2114654162621.

It is an arithmetic number, because the mean of its divisors is an integer number (6343962487851).

Almost surely, 2^{21146541626165} is an apocalyptic number.

It is an amenable number.

21146541626165 is a deficient number, since it is larger than the sum of its proper divisors (4229308325239).

21146541626165 is an equidigital number, since it uses as much as digits as its factorization.

21146541626165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4229308325238.

The product of its digits is 2073600, while the sum is 50.

The spelling of 21146541626165 in words is "twenty-one trillion, one hundred forty-six billion, five hundred forty-one million, six hundred twenty-six thousand, one hundred sixty-five".