1218161938 has 8 divisors (see below), whose sum is σ = 2088277632. Its totient is φ = 522069396.

The previous prime is 1218161899. The next prime is 1218161939. The reversal of 1218161938 is 8391618121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1218161938.

It is not an unprimeable number, because it can be changed into a prime (1218161939) 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, 43505770 + ... + 43505797.

It is an arithmetic number, because the mean of its divisors is an integer number (261034704).

Almost surely, 2^1218161938 is an apocalyptic number.

1218161938 is a deficient number, since it is larger than the sum of its proper divisors (870115694).

1218161938 is an equidigital number, since it uses as much as digits as its factorization.

1218161938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87011576.

The product of its digits is 20736, while the sum is 40.

The square root of 1218161938 is about 34902.1766942980. The cubic root of 1218161938 is about 1067.9928418818.

The spelling of 1218161938 in words is "one billion, two hundred eighteen million, one hundred sixty-one thousand, nine hundred thirty-eight".