21116222564 has 12 divisors (see below), whose sum is σ = 36955139004. Its totient is φ = 10557611424.

The previous prime is 21116222537. The next prime is 21116222573. The reversal of 21116222564 is 46522261112.

It can be written as a sum of positive squares in 2 ways, for example, as 2889062500 + 18227160064 = 53750^2 + 135008^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21116222564.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20147 + ... + 206490.

It is an arithmetic number, because the mean of its divisors is an integer number (3079594917).

Almost surely, 2^21116222564 is an apocalyptic number.

It is an amenable number.

21116222564 is a deficient number, since it is larger than the sum of its proper divisors (15838916440).

21116222564 is a wasteful number, since it uses less digits than its factorization.

21116222564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249934 (or 249932 counting only the distinct ones).

The product of its digits is 11520, while the sum is 32.

Adding to 21116222564 its reverse (46522261112), we get a palindrome (67638483676).

The spelling of 21116222564 in words is "twenty-one billion, one hundred sixteen million, two hundred twenty-two thousand, five hundred sixty-four".