20686851 has 12 divisors (see below), whose sum is σ = 30050280. Its totient is φ = 13713120.

The previous prime is 20686847. The next prime is 20686871. The reversal of 20686851 is 15868602.

It is a happy number.

It is not a de Polignac number, because 20686851 - 2² = 20686847 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (20686871) 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 in 11 ways as a sum of consecutive naturals, for example, 4810 + ... + 8031.

It is an arithmetic number, because the mean of its divisors is an integer number (2504190).

Almost surely, 2^20686851 is an apocalyptic number.

20686851 is a deficient number, since it is larger than the sum of its proper divisors (9363429).

20686851 is a wasteful number, since it uses less digits than its factorization.

20686851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13026 (or 13023 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 20686851 is about 4548.2800045732. The cubic root of 20686851 is about 274.5141880052.

The spelling of 20686851 in words is "twenty million, six hundred eighty-six thousand, eight hundred fifty-one".