16916021 has 2 divisors, whose sum is σ = 16916022. Its totient is φ = 16916020.

The previous prime is 16915991. The next prime is 16916027. The reversal of 16916021 is 12061961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13359025 + 3556996 = 3655^2 + 1886^2 .

It is an emirp because it is prime and its reverse (12061961) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16916021 - 2¹⁸ = 16653877 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 (16916027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8458010 + 8458011.

It is an arithmetic number, because the mean of its divisors is an integer number (8458011).

Almost surely, 2^16916021 is an apocalyptic number.

It is an amenable number.

16916021 is a deficient number, since it is larger than the sum of its proper divisors (1).

16916021 is an equidigital number, since it uses as much as digits as its factorization.

16916021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 26.

The square root of 16916021 is about 4112.9090678010. The cubic root of 16916021 is about 256.7040606300.

Adding to 16916021 its reverse (12061961), we get a palindrome (28977982).

The spelling of 16916021 in words is "sixteen million, nine hundred sixteen thousand, twenty-one".