1218444909 has 16 divisors (see below), whose sum is σ = 1775414784. Its totient is φ = 737146800.

The previous prime is 1218444907. The next prime is 1218444917. The reversal of 1218444909 is 9094448121.

It is a happy number.

It is not a de Polignac number, because 1218444909 - 2¹ = 1218444907 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218444907) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13489 + ... + 51174.

It is an arithmetic number, because the mean of its divisors is an integer number (110963424).

Almost surely, 2^1218444909 is an apocalyptic number.

It is an amenable number.

1218444909 is a deficient number, since it is larger than the sum of its proper divisors (556969875).

1218444909 is a wasteful number, since it uses less digits than its factorization.

1218444909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65248.

The product of its (nonzero) digits is 82944, while the sum is 42.

The square root of 1218444909 is about 34906.2302318655. The cubic root of 1218444909 is about 1068.0755313819.

The spelling of 1218444909 in words is "one billion, two hundred eighteen million, four hundred forty-four thousand, nine hundred nine".