21044101138225 has 27 divisors (see below), whose sum is σ = 28682931988011. Its totient is φ = 15304617332400.

The previous prime is 21044101138211. The next prime is 21044101138297. The reversal of 21044101138225 is 52283110144012.

The square root of 21044101138225 is 4587385.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 7575876409761 + 13468224728464 = 2752431^2 + 3669908^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21044101138225 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 252264472 + ... + 252347878.

Almost surely, 2^{21044101138225} is an apocalyptic number.

21044101138225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21044101138225 is the 4587385-th square number.

21044101138225 is the 2293693-rd centered octagonal number.

It is an amenable number.

21044101138225 is a deficient number, since it is larger than the sum of its proper divisors (7638830849786).

21044101138225 is an frugal number, since it uses more digits than its factorization.

21044101138225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166846 (or 83423 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 34.

The spelling of 21044101138225 in words is "twenty-one trillion, forty-four billion, one hundred one million, one hundred thirty-eight thousand, two hundred twenty-five".