21421100 has 18 divisors (see below), whose sum is σ = 46484004. Its totient is φ = 8568400.

The previous prime is 21421097. The next prime is 21421117. The reversal of 21421100 is 112412.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 107006 + ... + 107205.

Almost surely, 2^21421100 is an apocalyptic number.

21421100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21421100 is an abundant number, since it is smaller than the sum of its proper divisors (25062904).

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

21421100 is a wasteful number, since it uses less digits than its factorization.

21421100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214225 (or 214218 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21421100 is about 4628.2934219861. The cubic root of 21421100 is about 277.7243269007.

Adding to 21421100 its reverse (112412), we get a palindrome (21533512).

The spelling of 21421100 in words is "twenty-one million, four hundred twenty-one thousand, one hundred".