20209786 has 4 divisors (see below), whose sum is σ = 30314682. Its totient is φ = 10104892.

The previous prime is 20209771. The next prime is 20209789. The reversal of 20209786 is 68790202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 4761 = 4495^2 + 69^2 .

It is not an unprimeable number, because it can be changed into a prime (20209789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5052445 + ... + 5052448.

Almost surely, 2^20209786 is an apocalyptic number.

20209786 is a deficient number, since it is larger than the sum of its proper divisors (10104896).

20209786 is a wasteful number, since it uses less digits than its factorization.

20209786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10104895.

The product of its (nonzero) digits is 12096, while the sum is 34.

The square root of 20209786 is about 4495.5295572379. The cubic root of 20209786 is about 272.3875404983.

Adding to 20209786 its reverse (68790202), we get a palindrome (88999988).

The spelling of 20209786 in words is "twenty million, two hundred nine thousand, seven hundred eighty-six".