1289920 has 56 divisors (see below), whose sum is σ = 3200400. Its totient is φ = 494592.

The previous prime is 1289881. The next prime is 1289921. The reversal of 1289920 is 299821.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1289921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9211 + ... + 9349.

It is an arithmetic number, because the mean of its divisors is an integer number (57150).

2^1289920 is an apocalyptic number.

1289920 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 1289920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1600200).

1289920 is an abundant number, since it is smaller than the sum of its proper divisors (1910480).

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

1289920 is a wasteful number, since it uses less digits than its factorization.

1289920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185 (or 175 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 1289920 is about 1135.7464505778. The cubic root of 1289920 is about 108.8564729892.

Subtracting from 1289920 its reverse (299821), we obtain a palindrome (990099).

It can be divided in two parts, 1289 and 920, that added together give a square (2209 = 47²).

The spelling of 1289920 in words is "one million, two hundred eighty-nine thousand, nine hundred twenty".