21001221112 has 8 divisors (see below), whose sum is σ = 39377289600. Its totient is φ = 10500610552.

The previous prime is 21001221091. The next prime is 21001221119. The reversal of 21001221112 is 21112210012.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×21001221112² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21001221092 and 21001221101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001221119) by changing a digit.

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, 1312576312 + ... + 1312576327.

It is an arithmetic number, because the mean of its divisors is an integer number (4922161200).

Almost surely, 2^21001221112 is an apocalyptic number.

It is an amenable number.

21001221112 is a deficient number, since it is larger than the sum of its proper divisors (18376068488).

21001221112 is a wasteful number, since it uses less digits than its factorization.

21001221112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2625152645 (or 2625152641 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21001221112 its reverse (21112210012), we get a palindrome (42113431124).

It can be divided in two parts, 210012 and 21112, that multiplied together give a palindrome (4433773344).

The spelling of 21001221112 in words is "twenty-one billion, one million, two hundred twenty-one thousand, one hundred twelve".