21784200420 has 24 divisors (see below), whose sum is σ = 60995761344. Its totient is φ = 5809120096.

The previous prime is 21784200419. The next prime is 21784200421. The reversal of 21784200420 is 2400248712.

It is an interprime number because it is at equal distance from previous prime (21784200419) and next prime (21784200421).

It is a super-3 number, since 3×21784200420³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21784200421) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 181534944 + ... + 181535063.

It is an arithmetic number, because the mean of its divisors is an integer number (2541490056).

Almost surely, 2^21784200420 is an apocalyptic number.

21784200420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21784200420 is an abundant number, since it is smaller than the sum of its proper divisors (39211560924).

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

21784200420 is a wasteful number, since it uses less digits than its factorization.

21784200420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363070019 (or 363070017 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 30.

The spelling of 21784200420 in words is "twenty-one billion, seven hundred eighty-four million, two hundred thousand, four hundred twenty".