20421763 has 4 divisors (see below), whose sum is σ = 20756608. Its totient is φ = 20086920.

The previous prime is 20421749. The next prime is 20421767. The reversal of 20421763 is 36712402.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20421763 - 2⁹ = 20421251 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20421767) 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 3 ways as a sum of consecutive naturals, for example, 167331 + ... + 167452.

It is an arithmetic number, because the mean of its divisors is an integer number (5189152).

Almost surely, 2^20421763 is an apocalyptic number.

20421763 is a deficient number, since it is larger than the sum of its proper divisors (334845).

20421763 is an equidigital number, since it uses as much as digits as its factorization.

20421763 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334844.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 20421763 is about 4519.0444786481. The cubic root of 20421763 is about 273.3365722731.

The spelling of 20421763 in words is "twenty million, four hundred twenty-one thousand, seven hundred sixty-three".