2581328549 has 4 divisors (see below), whose sum is σ = 2582684064. Its totient is φ = 2579973036.

The previous prime is 2581328537. The next prime is 2581328557. The reversal of 2581328549 is 9458231852.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2581328549 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 (2581328149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 674897 + ... + 678710.

It is an arithmetic number, because the mean of its divisors is an integer number (645671016).

Almost surely, 2^2581328549 is an apocalyptic number.

It is an amenable number.

2581328549 is a deficient number, since it is larger than the sum of its proper divisors (1355515).

2581328549 is a wasteful number, since it uses less digits than its factorization.

2581328549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1355514.

The product of its digits is 691200, while the sum is 47.

The square root of 2581328549 is about 50806.7766050947. The cubic root of 2581328549 is about 1371.7693495841.

The spelling of 2581328549 in words is "two billion, five hundred eighty-one million, three hundred twenty-eight thousand, five hundred forty-nine".