20421075 has 48 divisors (see below), whose sum is σ = 35935200. Its totient is φ = 10214400.

The previous prime is 20421073. The next prime is 20421103. The reversal of 20421075 is 57012402.

It is not a de Polignac number, because 20421075 - 2¹ = 20421073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20421073) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 89061 + ... + 89289.

It is an arithmetic number, because the mean of its divisors is an integer number (748650).

Almost surely, 2^20421075 is an apocalyptic number.

20421075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20421075 is a deficient number, since it is larger than the sum of its proper divisors (15514125).

20421075 is a wasteful number, since it uses less digits than its factorization.

20421075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312 (or 307 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 20421075 is about 4518.9683557201. The cubic root of 20421075 is about 273.3335027099. Note that the first 3 decimals are identical.

Adding to 20421075 its reverse (57012402), we get a palindrome (77433477).

The spelling of 20421075 in words is "twenty million, four hundred twenty-one thousand, seventy-five".