164186021 has 4 divisors (see below), whose sum is σ = 164626572. Its totient is φ = 163745472.

The previous prime is 164185991. The next prime is 164186039. The reversal of 164186021 is 120681461.

164186021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120681461 = 6869 ⋅17569.

It can be written as a sum of positive squares in 2 ways, for example, as 47761921 + 116424100 = 6911^2 + 10790^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-164186021 is a prime.

It is a super-5 number, since 5×164186021⁵ (a number of 42 digits) contains 55555 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164186921) 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, 219716 + ... + 220461.

It is an arithmetic number, because the mean of its divisors is an integer number (41156643).

Almost surely, 2^164186021 is an apocalyptic number.

It is an amenable number.

164186021 is a deficient number, since it is larger than the sum of its proper divisors (440551).

164186021 is an equidigital number, since it uses as much as digits as its factorization.

164186021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 440550.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 164186021 is about 12813.5093163427. The cubic root of 164186021 is about 547.5772453441.

The spelling of 164186021 in words is "one hundred sixty-four million, one hundred eighty-six thousand, twenty-one".