1561440 has 48 divisors (see below), whose sum is σ = 4920048. Its totient is φ = 416256.

The previous prime is 1561429. The next prime is 1561453. The reversal of 1561440 is 441651.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

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, 1147 + ... + 2106.

It is an arithmetic number, because the mean of its divisors is an integer number (102501).

2^1561440 is an apocalyptic number.

1561440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1561440 is an abundant number, since it is smaller than the sum of its proper divisors (3358608).

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

1561440 is a wasteful number, since it uses less digits than its factorization.

1561440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3271 (or 3263 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 1561440 is about 1249.5759280652. The cubic root of 1561440 is about 116.0134744554.

It can be divided in two parts, 156 and 1440, that added together give a triangular number (1596 = T₅₆).

The spelling of 1561440 in words is "one million, five hundred sixty-one thousand, four hundred forty".