20816669 has 2 divisors, whose sum is σ = 20816670. Its totient is φ = 20816668.

The previous prime is 20816659. The next prime is 20816689. The reversal of 20816669 is 96661802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20748025 + 68644 = 4555^2 + 262^2 .

It is a cyclic number.

It is not a de Polignac number, because 20816669 - 2⁸ = 20816413 is a prime.

It is a super-2 number, since 2×20816669² = 866667416511122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20816659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10408334 + 10408335.

It is an arithmetic number, because the mean of its divisors is an integer number (10408335).

Almost surely, 2^20816669 is an apocalyptic number.

It is an amenable number.

20816669 is a deficient number, since it is larger than the sum of its proper divisors (1).

20816669 is an equidigital number, since it uses as much as digits as its factorization.

20816669 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 38.

The square root of 20816669 is about 4562.5287944297. The cubic root of 20816669 is about 275.0872186159.

The spelling of 20816669 in words is "twenty million, eight hundred sixteen thousand, six hundred sixty-nine".