20686849 has 4 divisors (see below), whose sum is σ = 20824000. Its totient is φ = 20549700.

The previous prime is 20686847. The next prime is 20686871. The reversal of 20686849 is 94868602.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20686849 - 2¹ = 20686847 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20686843) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68349 + ... + 68650.

It is an arithmetic number, because the mean of its divisors is an integer number (5206000).

Almost surely, 2^20686849 is an apocalyptic number.

It is an amenable number.

20686849 is a deficient number, since it is larger than the sum of its proper divisors (137151).

20686849 is a wasteful number, since it uses less digits than its factorization.

20686849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137150.

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 20686849 is about 4548.2797847098. The cubic root of 20686849 is about 274.5141791586.

The spelling of 20686849 in words is "twenty million, six hundred eighty-six thousand, eight hundred forty-nine".