20421885 has 32 divisors (see below), whose sum is σ = 36247680. Its totient is φ = 9734400.

The previous prime is 20421883. The next prime is 20421899. The reversal of 20421885 is 58812402.

It is not a de Polignac number, because 20421885 - 2¹ = 20421883 is a prime.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20421881) 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 31 ways as a sum of consecutive naturals, for example, 9051 + ... + 11079.

It is an arithmetic number, because the mean of its divisors is an integer number (1132740).

Almost surely, 2^20421885 is an apocalyptic number.

It is an amenable number.

20421885 is a deficient number, since it is larger than the sum of its proper divisors (15825795).

20421885 is a wasteful number, since it uses less digits than its factorization.

20421885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2109.

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 20421885 is about 4519.0579770567. The cubic root of 20421885 is about 273.3371165779.

The spelling of 20421885 in words is "twenty million, four hundred twenty-one thousand, eight hundred eighty-five".