2581987 has 4 divisors (see below), whose sum is σ = 2597616. Its totient is φ = 2566360.

The previous prime is 2581973. The next prime is 2581991. The reversal of 2581987 is 7891852.

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

It is a cyclic number.

It is not a de Polignac number, because 2581987 - 2¹¹ = 2579939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2581907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7564 + ... + 7897.

It is an arithmetic number, because the mean of its divisors is an integer number (649404).

2^2581987 is an apocalyptic number.

2581987 is a deficient number, since it is larger than the sum of its proper divisors (15629).

2581987 is a wasteful number, since it uses less digits than its factorization.

2581987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15628.

The product of its digits is 40320, while the sum is 40.

The square root of 2581987 is about 1606.8562474596. The cubic root of 2581987 is about 137.1885977655.

The spelling of 2581987 in words is "two million, five hundred eighty-one thousand, nine hundred eighty-seven".