20421589 has 8 divisors (see below), whose sum is σ = 20875320. Its totient is φ = 19970496.

The previous prime is 20421571. The next prime is 20421593. The reversal of 20421589 is 98512402.

It can be written as a sum of positive squares in 4 ways, for example, as 9199089 + 11222500 = 3033^2 + 3350^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20421589 - 2¹¹ = 20419541 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20421589.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421389) 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, 26599 + ... + 27355.

It is an arithmetic number, because the mean of its divisors is an integer number (2609415).

Almost surely, 2^20421589 is an apocalyptic number.

It is an amenable number.

20421589 is a deficient number, since it is larger than the sum of its proper divisors (453731).

20421589 is an equidigital number, since it uses as much as digits as its factorization.

20421589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1319.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 20421589 is about 4519.0252267497. The cubic root of 20421589 is about 273.3357959657.

It can be divided in two parts, 204215 and 89, that added together give a square (204304 = 452²).

The spelling of 20421589 in words is "twenty million, four hundred twenty-one thousand, five hundred eighty-nine".