20051686 has 4 divisors (see below), whose sum is σ = 30077532. Its totient is φ = 10025842.

The previous prime is 20051683. The next prime is 20051711. The reversal of 20051686 is 68615002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68615002 = 2 ⋅34307501.

It is a super-2 number, since 2×20051686² = 804140222885192, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20051683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5012920 + ... + 5012923.

It is an arithmetic number, because the mean of its divisors is an integer number (7519383).

Almost surely, 2^20051686 is an apocalyptic number.

20051686 is a deficient number, since it is larger than the sum of its proper divisors (10025846).

20051686 is a wasteful number, since it uses less digits than its factorization.

20051686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10025845.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 20051686 is about 4477.9108968357. The cubic root of 20051686 is about 271.6753895017.

Adding to 20051686 its reverse (68615002), we get a palindrome (88666688).

The spelling of 20051686 in words is "twenty million, fifty-one thousand, six hundred eighty-six".