1818971225 has 6 divisors (see below), whose sum is σ = 2255524350. Its totient is φ = 1455176960.

The previous prime is 1818971201. The next prime is 1818971227. The reversal of 1818971225 is 5221798181.

It can be written as a sum of positive squares in 3 ways, for example, as 48497296 + 1770473929 = 6964^2 + 42077^2 .

It is not a de Polignac number, because 1818971225 - 2²⁶ = 1751862361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1818971227) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36379400 + ... + 36379449.

It is an arithmetic number, because the mean of its divisors is an integer number (375920725).

Almost surely, 2^1818971225 is an apocalyptic number.

It is an amenable number.

1818971225 is a deficient number, since it is larger than the sum of its proper divisors (436553125).

1818971225 is an equidigital number, since it uses as much as digits as its factorization.

1818971225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72758859 (or 72758854 counting only the distinct ones).

The product of its digits is 80640, while the sum is 44.

The square root of 1818971225 is about 42649.3988820476. The cubic root of 1818971225 is about 1220.6990585146.

The spelling of 1818971225 in words is "one billion, eight hundred eighteen million, nine hundred seventy-one thousand, two hundred twenty-five".