16216404521 has 2 divisors, whose sum is σ = 16216404522. Its totient is φ = 16216404520.

The previous prime is 16216404509. The next prime is 16216404539. The reversal of 16216404521 is 12540461261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11194698025 + 5021706496 = 105805^2 + 70864^2 .

It is an emirp because it is prime and its reverse (12540461261) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16216404521 is a prime.

It is not a weakly prime, because it can be changed into another prime (16216494521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8108202260 + 8108202261.

It is an arithmetic number, because the mean of its divisors is an integer number (8108202261).

Almost surely, 2^16216404521 is an apocalyptic number.

It is an amenable number.

16216404521 is a deficient number, since it is larger than the sum of its proper divisors (1).

16216404521 is an equidigital number, since it uses as much as digits as its factorization.

16216404521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 32.

Adding to 16216404521 its reverse (12540461261), we get a palindrome (28756865782).

The spelling of 16216404521 in words is "sixteen billion, two hundred sixteen million, four hundred four thousand, five hundred twenty-one".