1001808 has 50 divisors (see below), whose sum is σ = 2903274. Its totient is φ = 333504.

The previous prime is 1001807. The next prime is 1001809. The reversal of 1001808 is 8081001.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1001807) and next prime (1001809).

It can be written as a sum of positive squares in only one way, i.e., 627264 + 374544 = 792^2 + 612^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1001801) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 910 + ... + 1682.

2^1001808 is an apocalyptic number.

1001808 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 1001808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1451637).

1001808 is an abundant number, since it is smaller than the sum of its proper divisors (1901466).

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

1001808 is an equidigital number, since it uses as much as digits as its factorization.

1001808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 793 (or 778 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 1001808 is about 1000.9035917610. The cubic root of 1001808 is about 100.0602303824.

Adding to 1001808 its reverse (8081001), we get a palindrome (9082809).

It can be divided in two parts, 1001 and 808, that multiplied together give a palindrome (808808).

The spelling of 1001808 in words is "one million, one thousand, eight hundred eight".