21001100420 has 24 divisors (see below), whose sum is σ = 44760557184. Its totient is φ = 8275059936.

The previous prime is 21001100413. The next prime is 21001100503. The reversal of 21001100420 is 2400110012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7834892 + ... + 7837571.

It is an arithmetic number, because the mean of its divisors is an integer number (1865023216).

Almost surely, 2^21001100420 is an apocalyptic number.

21001100420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001100420 is an abundant number, since it is smaller than the sum of its proper divisors (23759456764).

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

21001100420 is a wasteful number, since it uses less digits than its factorization.

21001100420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15672539 (or 15672537 counting only the distinct ones).

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

Adding to 21001100420 its reverse (2400110012), we get a palindrome (23401210432).

The spelling of 21001100420 in words is "twenty-one billion, one million, one hundred thousand, four hundred twenty".