1398881988 has 216 divisors, whose sum is σ = 4454678592. Its totient is φ = 382003776.

The previous prime is 1398881987. The next prime is 1398881989. The reversal of 1398881988 is 8891888931.

It is an interprime number because it is at equal distance from previous prime (1398881987) and next prime (1398881989).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (1398881983) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1094806 + ... + 1096082.

It is an arithmetic number, because the mean of its divisors is an integer number (20623512).

Almost surely, 2^1398881988 is an apocalyptic number.

1398881988 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 1398881988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2227339296).

1398881988 is an abundant number, since it is smaller than the sum of its proper divisors (3055796604).

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

1398881988 is a wasteful number, since it uses less digits than its factorization.

1398881988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1333 (or 1312 counting only the distinct ones).

The product of its digits is 7962624, while the sum is 63.

The square root of 1398881988 is about 37401.6308200592. The cubic root of 1398881988 is about 1118.3910752387.

The spelling of 1398881988 in words is "one billion, three hundred ninety-eight million, eight hundred eighty-one thousand, nine hundred eighty-eight".