20641669 has 2 divisors, whose sum is σ = 20641670. Its totient is φ = 20641668.

The previous prime is 20641661. The next prime is 20641679. The reversal of 20641669 is 96614602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16916769 + 3724900 = 4113^2 + 1930^2 .

It is a cyclic number.

It is not a de Polignac number, because 20641669 - 2³ = 20641661 is a prime.

It is a super-2 number, since 2×20641669² = 852156998211122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20641661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10320834 + 10320835.

It is an arithmetic number, because the mean of its divisors is an integer number (10320835).

Almost surely, 2^20641669 is an apocalyptic number.

It is an amenable number.

20641669 is a deficient number, since it is larger than the sum of its proper divisors (1).

20641669 is an equidigital number, since it uses as much as digits as its factorization.

20641669 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 20641669 is about 4543.3103569974. The cubic root of 20641669 is about 274.3141875177.

The spelling of 20641669 in words is "twenty million, six hundred forty-one thousand, six hundred sixty-nine".