21042000420 has 96 divisors (see below), whose sum is σ = 68708640000. Its totient is φ = 4809595392.

The previous prime is 21042000377. The next prime is 21042000431. The reversal of 21042000420 is 2400024012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21042000420.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 490645 + ... + 531804.

It is an arithmetic number, because the mean of its divisors is an integer number (715715000).

Almost surely, 2^21042000420 is an apocalyptic number.

21042000420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21042000420 is an abundant number, since it is smaller than the sum of its proper divisors (47666639580).

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

21042000420 is a wasteful number, since it uses less digits than its factorization.

21042000420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1022482 (or 1022466 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 15.

Adding to 21042000420 its reverse (2400024012), we get a palindrome (23442024432).

The spelling of 21042000420 in words is "twenty-one billion, forty-two million, four hundred twenty", and thus it is an aban number.