1561340 has 48 divisors (see below), whose sum is σ = 3677184. Its totient is φ = 552000.

The previous prime is 1561337. The next prime is 1561349. The reversal of 1561340 is 431651.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561349) 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, 10265 + ... + 10415.

It is an arithmetic number, because the mean of its divisors is an integer number (76608).

2^1561340 is an apocalyptic number.

1561340 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 1561340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1838592).

1561340 is an abundant number, since it is smaller than the sum of its proper divisors (2115844).

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

1561340 is a wasteful number, since it uses less digits than its factorization.

1561340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218 (or 216 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 1561340 is about 1249.5359138496. The cubic root of 1561340 is about 116.0109977682.

Adding to 1561340 its reverse (431651), we get a palindrome (1992991).

The spelling of 1561340 in words is "one million, five hundred sixty-one thousand, three hundred forty".