1218328221 has 8 divisors (see below), whose sum is σ = 1772113824. Its totient is φ = 738380720.

The previous prime is 1218328211. The next prime is 1218328231. The reversal of 1218328221 is 1228238121.

It is an interprime number because it is at equal distance from previous prime (1218328211) and next prime (1218328231).

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

It is not a de Polignac number, because 1218328221 - 2⁶ = 1218328157 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218328211) 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, 18459486 + ... + 18459551.

It is an arithmetic number, because the mean of its divisors is an integer number (221514228).

Almost surely, 2^1218328221 is an apocalyptic number.

1218328221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1218328221 is a deficient number, since it is larger than the sum of its proper divisors (553785603).

1218328221 is a wasteful number, since it uses less digits than its factorization.

1218328221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36919051.

The product of its digits is 3072, while the sum is 30.

The square root of 1218328221 is about 34904.5587423763. The cubic root of 1218328221 is about 1068.0414344836.

It can be divided in two parts, 12183 and 28221, that added together give a palindrome (40404).

The spelling of 1218328221 in words is "one billion, two hundred eighteen million, three hundred twenty-eight thousand, two hundred twenty-one".