1218831900 has 144 divisors (see below), whose sum is σ = 4143151488. Its totient is φ = 272736000.

The previous prime is 1218831877. The next prime is 1218831959. The reversal of 1218831900 is 91388121.

It is a super-2 number, since 2×1218831900² = 2971102400915220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 28695 + ... + 57105.

Almost surely, 2^1218831900 is an apocalyptic number.

1218831900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1218831900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2071575744).

1218831900 is an abundant number, since it is smaller than the sum of its proper divisors (2924319588).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1218831900 is a wasteful number, since it uses less digits than its factorization.

1218831900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28452 (or 28445 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 33.

The square root of 1218831900 is about 34911.7730858804. The cubic root of 1218831900 is about 1068.1885967772.

The spelling of 1218831900 in words is "one billion, two hundred eighteen million, eight hundred thirty-one thousand, nine hundred".