164643421 has 2 divisors, whose sum is σ = 164643422. Its totient is φ = 164643420.

The previous prime is 164643403. The next prime is 164643467. The reversal of 164643421 is 124346461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 97239321 + 67404100 = 9861^2 + 8210^2 .

It is a cyclic number.

It is not a de Polignac number, because 164643421 - 2⁵ = 164643389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164643221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82321710 + 82321711.

It is an arithmetic number, because the mean of its divisors is an integer number (82321711).

Almost surely, 2^164643421 is an apocalyptic number.

It is an amenable number.

164643421 is a deficient number, since it is larger than the sum of its proper divisors (1).

164643421 is an equidigital number, since it uses as much as digits as its factorization.

164643421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 31.

The square root of 164643421 is about 12831.3452529343. The cubic root of 164643421 is about 548.0852658718.

Adding to 164643421 its reverse (124346461), we get a palindrome (288989882).

The spelling of 164643421 in words is "one hundred sixty-four million, six hundred forty-three thousand, four hundred twenty-one".