16418578225 has 45 divisors (see below), whose sum is σ = 23796296043. Its totient is φ = 11236926960.

The previous prime is 16418578217. The next prime is 16418578229. The reversal of 16418578225 is 52287581461.

The square root of 16418578225 is 128135.

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., 5910688161 + 10507890064 = 76881^2 + 102508^2 .

It is not a de Polignac number, because 16418578225 - 2³ = 16418578217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16418578229) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 31392814 + ... + 31393336.

Almost surely, 2^16418578225 is an apocalyptic number.

16418578225 is the 128135-th square number.

16418578225 is the 64068-th centered octagonal number.

It is an amenable number.

16418578225 is a deficient number, since it is larger than the sum of its proper divisors (7377717818).

16418578225 is an frugal number, since it uses more digits than its factorization.

16418578225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1084 (or 535 counting only the distinct ones).

The product of its digits is 1075200, while the sum is 49.

Multiplying 16418578225 by its sum of digits (49), we get a square (804510333025 = 896945²).

16418578225 divided by its sum of digits (49) gives a square (335073025 = 18305²).

The spelling of 16418578225 in words is "sixteen billion, four hundred eighteen million, five hundred seventy-eight thousand, two hundred twenty-five".