16904521 has 2 divisors, whose sum is σ = 16904522. Its totient is φ = 16904520.

The previous prime is 16904507. The next prime is 16904533. The reversal of 16904521 is 12540961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14930496 + 1974025 = 3864^2 + 1405^2 .

It is an emirp because it is prime and its reverse (12540961) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16904521 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16904521.

It is not a weakly prime, because it can be changed into another prime (16904561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8452260 + 8452261.

It is an arithmetic number, because the mean of its divisors is an integer number (8452261).

Almost surely, 2^16904521 is an apocalyptic number.

It is an amenable number.

16904521 is a deficient number, since it is larger than the sum of its proper divisors (1).

16904521 is an equidigital number, since it uses as much as digits as its factorization.

16904521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 16904521 is about 4111.5107928838. The cubic root of 16904521 is about 256.6458758295.

The spelling of 16904521 in words is "sixteen million, nine hundred four thousand, five hundred twenty-one".