2581551 has 40 divisors (see below), whose sum is σ = 4588320. Its totient is φ = 1415232.

The previous prime is 2581541. The next prime is 2581559. The reversal of 2581551 is 1551852.

It is not a de Polignac number, because 2581551 - 2⁶ = 2581487 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2581559) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 16365 + ... + 16521.

It is an arithmetic number, because the mean of its divisors is an integer number (114708).

2^2581551 is an apocalyptic number.

2581551 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

2581551 is a deficient number, since it is larger than the sum of its proper divisors (2006769).

2581551 is a wasteful number, since it uses less digits than its factorization.

2581551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 196 counting only the distinct ones).

The product of its digits is 2000, while the sum is 27.

The square root of 2581551 is about 1606.7205730929. The cubic root of 2581551 is about 137.1808753415.

The spelling of 2581551 in words is "two million, five hundred eighty-one thousand, five hundred fifty-one".