1213181388 has 120 divisors (see below), whose sum is σ = 3356288320. Its totient is φ = 382637520.

The previous prime is 1213181377. The next prime is 1213181413. The reversal of 1213181388 is 8831813121.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 1495503 + ... + 1496313.

Almost surely, 2^1213181388 is an apocalyptic number.

1213181388 is a gapful number since it is divisible by the number (18) 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 1213181388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1678144160).

1213181388 is an abundant number, since it is smaller than the sum of its proper divisors (2143106932).

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

1213181388 is an frugal number, since it uses more digits than its factorization.

1213181388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 861 (or 835 counting only the distinct ones).

The product of its digits is 9216, while the sum is 36.

The square root of 1213181388 is about 34830.7534802220. The cubic root of 1213181388 is about 1066.5353297061.

The spelling of 1213181388 in words is "one billion, two hundred thirteen million, one hundred eighty-one thousand, three hundred eighty-eight".