1581940 has 48 divisors (see below), whose sum is σ = 3669120. Its totient is φ = 570240.

The previous prime is 1581929. The next prime is 1581949. The reversal of 1581940 is 491851.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 1581899 and 1581908.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1581949) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8650 + ... + 8830.

It is an arithmetic number, because the mean of its divisors is an integer number (76440).

2^1581940 is an apocalyptic number.

1581940 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 1581940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1834560).

1581940 is an abundant number, since it is smaller than the sum of its proper divisors (2087180).

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

1581940 is a wasteful number, since it uses less digits than its factorization.

1581940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 1581940 is about 1257.7519628289. The cubic root of 1581940 is about 116.5189786539.

The spelling of 1581940 in words is "one million, five hundred eighty-one thousand, nine hundred forty".