21031304424 has 64 divisors (see below), whose sum is σ = 56646186240. Its totient is φ = 6468491520.

The previous prime is 21031304419. The next prime is 21031304447. The reversal of 21031304424 is 42440313012.

It is a super-3 number, since 3×21031304424³ (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 junction number, because it is equal to n+sod(n) for n = 21031304394 and 21031304403.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 820734 + ... + 845970.

It is an arithmetic number, because the mean of its divisors is an integer number (885096660).

Almost surely, 2^21031304424 is an apocalyptic number.

21031304424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21031304424 is an abundant number, since it is smaller than the sum of its proper divisors (35614881816).

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

21031304424 is a wasteful number, since it uses less digits than its factorization.

21031304424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27930 (or 27926 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 21031304424 its reverse (42440313012), we get a palindrome (63471617436).

The spelling of 21031304424 in words is "twenty-one billion, thirty-one million, three hundred four thousand, four hundred twenty-four".