164291821 has 2 divisors, whose sum is σ = 164291822. Its totient is φ = 164291820.

The previous prime is 164291819. The next prime is 164291833. The reversal of 164291821 is 128192461.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152250921 + 12040900 = 12339^2 + 3470^2 .

It is a cyclic number.

It is not a de Polignac number, because 164291821 - 2¹ = 164291819 is a prime.

Together with 164291819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164291861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82145910 + 82145911.

It is an arithmetic number, because the mean of its divisors is an integer number (82145911).

Almost surely, 2^164291821 is an apocalyptic number.

It is an amenable number.

164291821 is a deficient number, since it is larger than the sum of its proper divisors (1).

164291821 is an equidigital number, since it uses as much as digits as its factorization.

164291821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 34.

The square root of 164291821 is about 12817.6371067370. The cubic root of 164291821 is about 547.6948380451.

The spelling of 164291821 in words is "one hundred sixty-four million, two hundred ninety-one thousand, eight hundred twenty-one".