164742821 has 2 divisors, whose sum is σ = 164742822. Its totient is φ = 164742820.

The previous prime is 164742803. The next prime is 164742841. The reversal of 164742821 is 128247461.

164742821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 157377025 + 7365796 = 12545^2 + 2714^2 .

It is an emirp because it is prime and its reverse (128247461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 164742821 - 2²² = 160548517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (164742841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82371410 + 82371411.

It is an arithmetic number, because the mean of its divisors is an integer number (82371411).

Almost surely, 2^164742821 is an apocalyptic number.

It is an amenable number.

164742821 is a deficient number, since it is larger than the sum of its proper divisors (1).

164742821 is an equidigital number, since it uses as much as digits as its factorization.

164742821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21504, while the sum is 35.

The square root of 164742821 is about 12835.2179958114. The cubic root of 164742821 is about 548.1955419968.

The spelling of 164742821 in words is "one hundred sixty-four million, seven hundred forty-two thousand, eight hundred twenty-one".