1217213388 has 144 divisors (see below), whose sum is σ = 3282313216. Its totient is φ = 379779840.

The previous prime is 1217213381. The next prime is 1217213399. The reversal of 1217213388 is 8833127121.

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

It is not an unprimeable number, because it can be changed into a prime (1217213381) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5458245 + ... + 5458467.

Almost surely, 2^1217213388 is an apocalyptic number.

1217213388 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 1217213388, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1641156608).

1217213388 is an abundant number, since it is smaller than the sum of its proper divisors (2065099828).

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

1217213388 is a wasteful number, since it uses less digits than its factorization.

1217213388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404 (or 399 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 1217213388 is about 34888.5853539521. The cubic root of 1217213388 is about 1067.7155641144.

The spelling of 1217213388 in words is "one billion, two hundred seventeen million, two hundred thirteen thousand, three hundred eighty-eight".