21116449225 has 9 divisors (see below), whose sum is σ = 26185298023. Its totient is φ = 16892578120.

The previous prime is 21116449223. The next prime is 21116449229. The reversal of 21116449225 is 52294461112.

The square root of 21116449225 is 145315.

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., 7601921721 + 13514527504 = 87189^2 + 116252^2 .

It is not a de Polignac number, because 21116449225 - 2¹ = 21116449223 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21116449223) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 712044 + ... + 741106.

Almost surely, 2^21116449225 is an apocalyptic number.

21116449225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21116449225 is the 145315-th square number.

21116449225 is the 72658-th centered octagonal number.

It is an amenable number.

21116449225 is a deficient number, since it is larger than the sum of its proper divisors (5068848798).

21116449225 is an frugal number, since it uses more digits than its factorization.

21116449225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58136 (or 29068 counting only the distinct ones).

The product of its digits is 34560, while the sum is 37.

The spelling of 21116449225 in words is "twenty-one billion, one hundred sixteen million, four hundred forty-nine thousand, two hundred twenty-five".