21220033424 has 10 divisors (see below), whose sum is σ = 41113814790. Its totient is φ = 10610016704.

The previous prime is 21220033411. The next prime is 21220033447. The reversal of 21220033424 is 42433002212.

It can be written as a sum of positive squares in only one way, i.e., 17466265600 + 3753767824 = 132160^2 + 61268^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21220033424.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 663126029 + ... + 663126060.

It is an arithmetic number, because the mean of its divisors is an integer number (4111381479).

Almost surely, 2^21220033424 is an apocalyptic number.

It is an amenable number.

21220033424 is a deficient number, since it is larger than the sum of its proper divisors (19893781366).

21220033424 is a wasteful number, since it uses less digits than its factorization.

21220033424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1326252097 (or 1326252091 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 23.

Adding to 21220033424 its reverse (42433002212), we get a palindrome (63653035636).

The spelling of 21220033424 in words is "twenty-one billion, two hundred twenty million, thirty-three thousand, four hundred twenty-four".