16504421 has 2 divisors, whose sum is σ = 16504422. Its totient is φ = 16504420.

The previous prime is 16504417. The next prime is 16504457. The reversal of 16504421 is 12440561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15888196 + 616225 = 3986^2 + 785^2 .

It is a cyclic number.

It is not a de Polignac number, because 16504421 - 2² = 16504417 is a prime.

It is a Chen prime.

It is equal to p_1061456 and since 16504421 and 1061456 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16504471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8252210 + 8252211.

It is an arithmetic number, because the mean of its divisors is an integer number (8252211).

Almost surely, 2^16504421 is an apocalyptic number.

It is an amenable number.

16504421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16504421 is an equidigital number, since it uses as much as digits as its factorization.

16504421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 16504421 is about 4062.5633533522. The cubic root of 16504421 is about 254.6049039832.

Adding to 16504421 its reverse (12440561), we get a palindrome (28944982).

The spelling of 16504421 in words is "sixteen million, five hundred four thousand, four hundred twenty-one".