165732821 has 2 divisors, whose sum is σ = 165732822. Its totient is φ = 165732820.

The previous prime is 165732803. The next prime is 165732901. The reversal of 165732821 is 128237561.

It is a happy number.

165732821 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., 116942596 + 48790225 = 10814^2 + 6985^2 .

It is an emirp because it is prime and its reverse (128237561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 165732821 - 2¹⁴ = 165716437 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165732221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82866410 + 82866411.

It is an arithmetic number, because the mean of its divisors is an integer number (82866411).

Almost surely, 2^165732821 is an apocalyptic number.

It is an amenable number.

165732821 is a deficient number, since it is larger than the sum of its proper divisors (1).

165732821 is an equidigital number, since it uses as much as digits as its factorization.

165732821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20160, while the sum is 35.

The square root of 165732821 is about 12873.7259952199. The cubic root of 165732821 is about 549.2914523306.

The spelling of 165732821 in words is "one hundred sixty-five million, seven hundred thirty-two thousand, eight hundred twenty-one".