20421164 has 12 divisors (see below), whose sum is σ = 36071784. Its totient is φ = 10114944.

The previous prime is 20421103. The next prime is 20421179. The reversal of 20421164 is 46112402.

It is a super-2 number, since 2×20421164² = 834047878229792, which contains 22 as substring.

It is an unprimeable number.

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, 23429 + ... + 24284.

It is an arithmetic number, because the mean of its divisors is an integer number (3005982).

Almost surely, 2^20421164 is an apocalyptic number.

It is an amenable number.

20421164 is a deficient number, since it is larger than the sum of its proper divisors (15650620).

20421164 is a wasteful number, since it uses less digits than its factorization.

20421164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47824 (or 47822 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 20421164 is about 4518.9782030897. The cubic root of 20421164 is about 273.3338997939. Note that the first 3 decimals are identical.

Adding to 20421164 its reverse (46112402), we get a palindrome (66533566).

The spelling of 20421164 in words is "twenty million, four hundred twenty-one thousand, one hundred sixty-four".