20206556 has 12 divisors (see below), whose sum is σ = 35961240. Its totient is φ = 9931920.

The previous prime is 20206493. The next prime is 20206577. The reversal of 20206556 is 65560202.

It is a happy number.

It is a super-2 number, since 2×20206556² = 816609810762272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 42575 + ... + 43046.

It is an arithmetic number, because the mean of its divisors is an integer number (2996770).

Almost surely, 2^20206556 is an apocalyptic number.

It is an amenable number.

20206556 is a deficient number, since it is larger than the sum of its proper divisors (15754684).

20206556 is a wasteful number, since it uses less digits than its factorization.

20206556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85684 (or 85682 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 20206556 is about 4495.1702971078. The cubic root of 20206556 is about 272.3730284095.

Adding to 20206556 its reverse (65560202), we get a palindrome (85766758).

The spelling of 20206556 in words is "twenty million, two hundred six thousand, five hundred fifty-six".