20421875 has 14 divisors (see below), whose sum is σ = 25546548. Its totient is φ = 16325000.

The previous prime is 20421871. The next prime is 20421881. The reversal of 20421875 is 57812402.

It is not a de Polignac number, because 20421875 - 2² = 20421871 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20421871) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 14972 + ... + 16278.

Almost surely, 2^20421875 is an apocalyptic number.

20421875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20421875 is a deficient number, since it is larger than the sum of its proper divisors (5124673).

20421875 is an frugal number, since it uses more digits than its factorization.

20421875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1337 (or 1312 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 20421875 is about 4519.0568706313. The cubic root of 20421875 is about 273.3370719629.

The spelling of 20421875 in words is "twenty million, four hundred twenty-one thousand, eight hundred seventy-five".