20421100 has 36 divisors (see below), whose sum is σ = 50646064. Its totient is φ = 7001280.

The previous prime is 20421073. The next prime is 20421103. The reversal of 20421100 is 112402.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (20421103) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13887 + ... + 15286.

Almost surely, 2^20421100 is an apocalyptic number.

20421100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20421100 is an abundant number, since it is smaller than the sum of its proper divisors (30224964).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20421100 is a wasteful number, since it uses less digits than its factorization.

20421100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29194 (or 29187 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 20421100 is about 4518.9711218374. The cubic root of 20421100 is about 273.3336142505. Note that the first 3 decimals are identical.

Adding to 20421100 its reverse (112402), we get a palindrome (20533502).

The spelling of 20421100 in words is "twenty million, four hundred twenty-one thousand, one hundred".