16545821 has 2 divisors, whose sum is σ = 16545822. Its totient is φ = 16545820.

The previous prime is 16545797. The next prime is 16545853. The reversal of 16545821 is 12854561.

It is an a-pointer prime, because the next prime (16545853) can be obtained adding 16545821 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15132100 + 1413721 = 3890^2 + 1189^2 .

It is an emirp because it is prime and its reverse (12854561) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16545821 - 2¹⁸ = 16283677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16545421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8272910 + 8272911.

It is an arithmetic number, because the mean of its divisors is an integer number (8272911).

Almost surely, 2^16545821 is an apocalyptic number.

It is an amenable number.

16545821 is a deficient number, since it is larger than the sum of its proper divisors (1).

16545821 is an equidigital number, since it uses as much as digits as its factorization.

16545821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9600, while the sum is 32.

The square root of 16545821 is about 4067.6554672194. The cubic root of 16545821 is about 254.8176114720.

The spelling of 16545821 in words is "sixteen million, five hundred forty-five thousand, eight hundred twenty-one".