1887561 has 36 divisors (see below), whose sum is σ = 3168828. Its totient is φ = 1078272.

The previous prime is 1887539. The next prime is 1887563. The reversal of 1887561 is 1657881.

1887561 is a `hidden beast` number, since 18 + 87 + 561 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 81225 + 1806336 = 285^2 + 1344^2 .

It is not a de Polignac number, because 1887561 - 2⁷ = 1887433 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1887563) 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 35 ways as a sum of consecutive naturals, for example, 25821 + ... + 25893.

It is an arithmetic number, because the mean of its divisors is an integer number (88023).

2^1887561 is an apocalyptic number.

It is an amenable number.

1887561 is a deficient number, since it is larger than the sum of its proper divisors (1281267).

1887561 is a wasteful number, since it uses less digits than its factorization.

1887561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122 (or 106 counting only the distinct ones).

The product of its digits is 13440, while the sum is 36.

The square root of 1887561 is about 1373.8853663971. The cubic root of 1887561 is about 123.5853518947.

The spelling of 1887561 in words is "one million, eight hundred eighty-seven thousand, five hundred sixty-one".