21111144025 has 12 divisors (see below), whose sum is σ = 26229264300. Its totient is φ = 16855724480.

The previous prime is 21111144013. The next prime is 21111144029. The reversal of 21111144025 is 52044111112.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 235806736 + 20875337289 = 15356^2 + 144483^2 .

It is not a de Polignac number, because 21111144025 - 2¹⁵ = 21111111257 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21111143987 and 21111144005.

It is not an unprimeable number, because it can be changed into a prime (21111144029) 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 in 11 ways as a sum of consecutive naturals, for example, 816790 + ... + 842239.

It is an arithmetic number, because the mean of its divisors is an integer number (2185772025).

Almost surely, 2^21111144025 is an apocalyptic number.

21111144025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21111144025 is a deficient number, since it is larger than the sum of its proper divisors (5118120275).

21111144025 is a wasteful number, since it uses less digits than its factorization.

21111144025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1659548 (or 1659543 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 22.

Adding to 21111144025 its reverse (52044111112), we get a palindrome (73155255137).

The spelling of 21111144025 in words is "twenty-one billion, one hundred eleven million, one hundred forty-four thousand, twenty-five".