1289809920 has 208 divisors, whose sum is σ = 4718016000. Its totient is φ = 294715392.

The previous prime is 1289809919. The next prime is 1289809931. The reversal of 1289809920 is 299089821.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 1289809920.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 428581 + ... + 431579.

Almost surely, 2^1289809920 is an apocalyptic number.

1289809920 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 1289809920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2359008000).

1289809920 is an abundant number, since it is smaller than the sum of its proper divisors (3428206080).

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

1289809920 is an equidigital number, since it uses as much as digits as its factorization.

1289809920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3038 (or 3016 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 48.

The square root of 1289809920 is about 35913.9237622402. The cubic root of 1289809920 is about 1088.5337634723.

The spelling of 1289809920 in words is "one billion, two hundred eighty-nine million, eight hundred nine thousand, nine hundred twenty".