9917172225 has 45 divisors (see below), whose sum is σ = 18378335833. Its totient is φ = 5286768480.

The previous prime is 9917172193. The next prime is 9917172277. The reversal of 9917172225 is 5222717199.

The square root of 9917172225 is 99585.

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

9917172225 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 2784356289 + 7132815936 = 52767^2 + 84456^2 .

It is a tau number, because it is divible by the number of its divisors (45).

It is not a de Polignac number, because 9917172225 - 2⁵ = 9917172193 is a prime.

It is a super-2 number, since 2×9917172225² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 4480219 + ... + 4482431.

Almost surely, 2^9917172225 is an apocalyptic number.

9917172225 is the 99585-th square number.

9917172225 is the 49793-rd centered octagonal number.

It is an amenable number.

9917172225 is a deficient number, since it is larger than the sum of its proper divisors (8461163608).

9917172225 is an frugal number, since it uses more digits than its factorization.

9917172225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4448 (or 2221 counting only the distinct ones).

The product of its digits is 158760, while the sum is 45.

The cubic root of 9917172225 is about 2148.4699570167.

It can be divided in two parts, 99171 and 72225, that added together give a square (171396 = 414²).

The spelling of 9917172225 in words is "nine billion, nine hundred seventeen million, one hundred seventy-two thousand, two hundred twenty-five".