164042821 has 4 divisors (see below), whose sum is σ = 169699500. Its totient is φ = 158386144.

The previous prime is 164042819. The next prime is 164042849. The reversal of 164042821 is 128240461.

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 38266596 + 125776225 = 6186^2 + 11215^2 .

It is a cyclic number.

It is not a de Polignac number, because 164042821 - 2¹ = 164042819 is a prime.

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 164042821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164042861) 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, 2828296 + ... + 2828353.

It is an arithmetic number, because the mean of its divisors is an integer number (42424875).

Almost surely, 2^164042821 is an apocalyptic number.

It is an amenable number.

164042821 is a deficient number, since it is larger than the sum of its proper divisors (5656679).

164042821 is an equidigital number, since it uses as much as digits as its factorization.

164042821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5656678.

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 164042821 is about 12807.9202449110. The cubic root of 164042821 is about 547.4180034693.

The spelling of 164042821 in words is "one hundred sixty-four million, forty-two thousand, eight hundred twenty-one".