21004443240 has 96 divisors (see below), whose sum is σ = 69262633440. Its totient is φ = 5091982720.

The previous prime is 21004443233. The next prime is 21004443269. The reversal of 21004443240 is 4234440012.

It is a happy number.

It is a super-3 number, since 3×21004443240³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21004443240.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 708774 + ... + 737813.

It is an arithmetic number, because the mean of its divisors is an integer number (721485765).

Almost surely, 2^21004443240 is an apocalyptic number.

21004443240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21004443240 is an abundant number, since it is smaller than the sum of its proper divisors (48258190200).

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

21004443240 is a wasteful number, since it uses less digits than its factorization.

21004443240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1446623 (or 1446608 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 24.

Adding to 21004443240 its reverse (4234440012), we get a palindrome (25238883252).

The spelling of 21004443240 in words is "twenty-one billion, four million, four hundred forty-three thousand, two hundred forty".