20421583 has 12 divisors (see below), whose sum is σ = 25583880. Its totient is φ = 16157232.

The previous prime is 20421571. The next prime is 20421593. The reversal of 20421583 is 38512402.

It is a de Polignac number, because none of the positive numbers 2^k-20421583 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15393 + ... + 16666.

It is an arithmetic number, because the mean of its divisors is an integer number (2131990).

Almost surely, 2^20421583 is an apocalyptic number.

20421583 is a deficient number, since it is larger than the sum of its proper divisors (5162297).

20421583 is a wasteful number, since it uses less digits than its factorization.

20421583 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32086 (or 32079 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 20421583 is about 4519.0245628897. The cubic root of 20421583 is about 273.3357691964.

Adding to 20421583 its reverse (38512402), we get a palindrome (58933985).

The spelling of 20421583 in words is "twenty million, four hundred twenty-one thousand, five hundred eighty-three".