20805669 has 6 divisors (see below), whose sum is σ = 30052646. Its totient is φ = 13870440.

The previous prime is 20805647. The next prime is 20805689. The reversal of 20805669 is 96650802.

It can be written as a sum of positive squares in only one way, i.e., 12320100 + 8485569 = 3510^2 + 2913^2 .

It is not a de Polignac number, because 20805669 - 2¹¹ = 20803621 is a prime.

It is a super-2 number, since 2×20805669² = 865751725075122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20805689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1155862 + ... + 1155879.

Almost surely, 2^20805669 is an apocalyptic number.

It is an amenable number.

20805669 is a deficient number, since it is larger than the sum of its proper divisors (9246977).

20805669 is a wasteful number, since it uses less digits than its factorization.

20805669 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2311747 (or 2311744 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 20805669 is about 4561.3231632937. The cubic root of 20805669 is about 275.0387559703.

The spelling of 20805669 in words is "twenty million, eight hundred five thousand, six hundred sixty-nine".