1218161989 has 8 divisors (see below), whose sum is σ = 1364820768. Its totient is φ = 1077489360.

The previous prime is 1218161939. The next prime is 1218161993. The reversal of 1218161989 is 9891618121.

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

It is a cyclic number.

It is not a de Polignac number, because 1218161989 - 2¹⁷ = 1218030917 is a prime.

It is a super-2 number, since 2×1218161989² = 2967837262888872242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

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 7 ways as a sum of consecutive naturals, for example, 1496107 + ... + 1496920.

It is an arithmetic number, because the mean of its divisors is an integer number (170602596).

Almost surely, 2^1218161989 is an apocalyptic number.

It is an amenable number.

1218161989 is a deficient number, since it is larger than the sum of its proper divisors (146658779).

1218161989 is a wasteful number, since it uses less digits than its factorization.

1218161989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2993075.

The product of its digits is 62208, while the sum is 46.

The square root of 1218161989 is about 34902.1774249115. The cubic root of 1218161989 is about 1067.9928567861.

The spelling of 1218161989 in words is "one billion, two hundred eighteen million, one hundred sixty-one thousand, nine hundred eighty-nine".