20684128 has 12 divisors (see below), whose sum is σ = 40721940. Its totient is φ = 10342048.

The previous prime is 20684117. The next prime is 20684143. The reversal of 20684128 is 82148602.

It is a super-2 number, since 2×20684128² = 855666302240768, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20684128.

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 as a sum of consecutive naturals, namely, 323158 + ... + 323221.

It is an arithmetic number, because the mean of its divisors is an integer number (3393495).

Almost surely, 2^20684128 is an apocalyptic number.

It is an amenable number.

20684128 is a deficient number, since it is larger than the sum of its proper divisors (20037812).

20684128 is an equidigital number, since it uses as much as digits as its factorization.

20684128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646389 (or 646381 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 20684128 is about 4547.9806507944. The cubic root of 20684128 is about 274.5021427543.

The spelling of 20684128 in words is "twenty million, six hundred eighty-four thousand, one hundred twenty-eight".