1001988 has 36 divisors (see below), whose sum is σ = 2728908. Its totient is φ = 308160.

The previous prime is 1001983. The next prime is 1001989. The reversal of 1001988 is 8891001.

It can be written as a sum of positive squares in 2 ways, for example, as 589824 + 412164 = 768^2 + 642^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001981) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 603 + ... + 1538.

It is an arithmetic number, because the mean of its divisors is an integer number (75803).

2^1001988 is an apocalyptic number.

1001988 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

1001988 is an abundant number, since it is smaller than the sum of its proper divisors (1726920).

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

1001988 is a wasteful number, since it uses less digits than its factorization.

1001988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2164 (or 2159 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The square root of 1001988 is about 1000.9935064724. The cubic root of 1001988 is about 100.0662228024.

Adding to 1001988 its reverse (8891001), we get a palindrome (9892989).

The spelling of 1001988 in words is "one million, one thousand, nine hundred eighty-eight".