21004431420 has 96 divisors (see below), whose sum is σ = 67233600000. Its totient is φ = 4799625984.

The previous prime is 21004431319. The next prime is 21004431421. The reversal of 21004431420 is 2413440012.

It is a super-2 number, since 2×21004431420² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004431421) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2410231 + ... + 2418929.

It is an arithmetic number, because the mean of its divisors is an integer number (700350000).

Almost surely, 2^21004431420 is an apocalyptic number.

21004431420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21004431420 is an abundant number, since it is smaller than the sum of its proper divisors (46229168580).

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

21004431420 is a wasteful number, since it uses less digits than its factorization.

21004431420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14467 (or 14465 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 21004431420 its reverse (2413440012), we get a palindrome (23417871432).

The spelling of 21004431420 in words is "twenty-one billion, four million, four hundred thirty-one thousand, four hundred twenty".