164388821 has 4 divisors (see below), whose sum is σ = 164862912. Its totient is φ = 163914732.

The previous prime is 164388811. The next prime is 164388853. The reversal of 164388821 is 128883461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-164388821 is a prime.

It is a super-3 number, since 3×164388821³ (a number of 26 digits) contains 333 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 (164388811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 236525 + ... + 237218.

It is an arithmetic number, because the mean of its divisors is an integer number (41215728).

Almost surely, 2^164388821 is an apocalyptic number.

It is an amenable number.

164388821 is a deficient number, since it is larger than the sum of its proper divisors (474091).

164388821 is an equidigital number, since it uses as much as digits as its factorization.

164388821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474090.

The product of its digits is 73728, while the sum is 41.

The square root of 164388821 is about 12821.4203971323. The cubic root of 164388821 is about 547.8026055263.

The spelling of 164388821 in words is "one hundred sixty-four million, three hundred eighty-eight thousand, eight hundred twenty-one".