1218642393 has 4 divisors (see below), whose sum is σ = 1624856528. Its totient is φ = 812428260.

The previous prime is 1218642389. The next prime is 1218642401. The reversal of 1218642393 is 3932468121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1218642393 - 2² = 1218642389 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1218642353) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203107063 + ... + 203107068.

It is an arithmetic number, because the mean of its divisors is an integer number (406214132).

Almost surely, 2^1218642393 is an apocalyptic number.

It is an amenable number.

1218642393 is a deficient number, since it is larger than the sum of its proper divisors (406214135).

1218642393 is an equidigital number, since it uses as much as digits as its factorization.

1218642393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406214134.

The product of its digits is 62208, while the sum is 39.

The square root of 1218642393 is about 34909.0588959370. The cubic root of 1218642393 is about 1068.1332323722.

The spelling of 1218642393 in words is "one billion, two hundred eighteen million, six hundred forty-two thousand, three hundred ninety-three".