21420589 has 8 divisors (see below), whose sum is σ = 22296960. Its totient is φ = 20553456.

The previous prime is 21420587. The next prime is 21420643. The reversal of 21420589 is 98502412.

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 21420589 - 2¹ = 21420587 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 21420589.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420587) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 2632 + ... + 7054.

It is an arithmetic number, because the mean of its divisors is an integer number (2787120).

Almost surely, 2^21420589 is an apocalyptic number.

21420589 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21420589 is a deficient number, since it is larger than the sum of its proper divisors (876371).

21420589 is a wasteful number, since it uses less digits than its factorization.

21420589 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4619.

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

The square root of 21420589 is about 4628.2382177239. The cubic root of 21420589 is about 277.7221185133.

The spelling of 21420589 in words is "twenty-one million, four hundred twenty thousand, five hundred eighty-nine".