20428689 has 8 divisors (see below), whose sum is σ = 27583360. Its totient is φ = 13446576.

The previous prime is 20428687. The next prime is 20428693. The reversal of 20428689 is 98682402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20428689 - 2¹ = 20428687 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20428687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42862 + ... + 43335.

It is an arithmetic number, because the mean of its divisors is an integer number (3447920).

Almost surely, 2^20428689 is an apocalyptic number.

It is an amenable number.

20428689 is a deficient number, since it is larger than the sum of its proper divisors (7154671).

20428689 is an equidigital number, since it uses as much as digits as its factorization.

20428689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86279.

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 20428689 is about 4519.8107261256. The cubic root of 20428689 is about 273.3674692974.

It can be divided in two parts, 2042 and 8689, that added together give a triangular number (10731 = T₁₄₆).

The spelling of 20428689 in words is "twenty million, four hundred twenty-eight thousand, six hundred eighty-nine".