21121404244 has 6 divisors (see below), whose sum is σ = 36962457434. Its totient is φ = 10560702120.

The previous prime is 21121404223. The next prime is 21121404253. The reversal of 21121404244 is 44240412112.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18656281744 + 2465122500 = 136588^2 + 49650^2 .

It is a super-2 number, since 2×21121404244² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640175527 + ... + 2640175534.

Almost surely, 2^21121404244 is an apocalyptic number.

It is an amenable number.

21121404244 is a deficient number, since it is larger than the sum of its proper divisors (15841053190).

21121404244 is a wasteful number, since it uses less digits than its factorization.

21121404244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5280351065 (or 5280351063 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 25.

Adding to 21121404244 its reverse (44240412112), we get a palindrome (65361816356).

The spelling of 21121404244 in words is "twenty-one billion, one hundred twenty-one million, four hundred four thousand, two hundred forty-four".