1587661 has 4 divisors (see below), whose sum is σ = 1590300. Its totient is φ = 1585024.

The previous prime is 1587653. The next prime is 1587673. The reversal of 1587661 is 1667851.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 133225 + 1454436 = 365^2 + 1206^2 .

It is a cyclic number.

It is not a de Polignac number, because 1587661 - 2³ = 1587653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1587611) 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 3 ways as a sum of consecutive naturals, for example, 75 + ... + 1783.

It is an arithmetic number, because the mean of its divisors is an integer number (397575).

2^1587661 is an apocalyptic number.

1587661 is the 564-th centered decagonal number.

It is an amenable number.

1587661 is a deficient number, since it is larger than the sum of its proper divisors (2639).

1587661 is an equidigital number, since it uses as much as digits as its factorization.

1587661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2638.

The product of its digits is 10080, while the sum is 34.

The square root of 1587661 is about 1260.0242061167. The cubic root of 1587661 is about 116.6592711865.

The spelling of 1587661 in words is "one million, five hundred eighty-seven thousand, six hundred sixty-one".