1561240 has 32 divisors (see below), whose sum is σ = 3667680. Its totient is φ = 596992.

The previous prime is 1561213. The next prime is 1561243. The reversal of 1561240 is 421651.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561243) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 72 + ... + 1768.

It is an arithmetic number, because the mean of its divisors is an integer number (114615).

2^1561240 is an apocalyptic number.

1561240 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 1561240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1833840).

1561240 is an abundant number, since it is smaller than the sum of its proper divisors (2106440).

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

1561240 is a wasteful number, since it uses less digits than its factorization.

1561240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1731 (or 1727 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 1561240 is about 1249.4958983526. The cubic root of 1561240 is about 116.0085209753.

Adding to 1561240 its reverse (421651), we get a palindrome (1982891).

The spelling of 1561240 in words is "one million, five hundred sixty-one thousand, two hundred forty".