20421263 has 8 divisors (see below), whose sum is σ = 21580800. Its totient is φ = 19284408.

The previous prime is 20421253. The next prime is 20421277. The reversal of 20421263 is 36212402.

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 20421263 - 2¹⁸ = 20159119 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421223) 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, 3803 + ... + 7436.

It is an arithmetic number, because the mean of its divisors is an integer number (2697600).

Almost surely, 2^20421263 is an apocalyptic number.

20421263 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

20421263 is a deficient number, since it is larger than the sum of its proper divisors (1159537).

20421263 is a wasteful number, since it uses less digits than its factorization.

20421263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11341.

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 20421263 is about 4518.9891568801. The cubic root of 20421263 is about 273.3343414927.

Adding to 20421263 its reverse (36212402), we get a palindrome (56633665).

The spelling of 20421263 in words is "twenty million, four hundred twenty-one thousand, two hundred sixty-three".