1289640 has 64 divisors (see below), whose sum is σ = 4224960. Its totient is φ = 312320.

The previous prime is 1289627. The next prime is 1289653. The reversal of 1289640 is 469821.

It is an interprime number because it is at equal distance from previous prime (1289627) and next prime (1289653).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 1289598 and 1289607.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 832 + ... + 1808.

It is an arithmetic number, because the mean of its divisors is an integer number (66015).

2^1289640 is an apocalyptic number.

1289640 is a gapful number since it is divisible by the number (10) 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 1289640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2112480).

1289640 is an abundant number, since it is smaller than the sum of its proper divisors (2935320).

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

1289640 is a wasteful number, since it uses less digits than its factorization.

1289640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1002 (or 998 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 1289640 is about 1135.6231769385. The cubic root of 1289640 is about 108.8485960103.

The spelling of 1289640 in words is "one million, two hundred eighty-nine thousand, six hundred forty".