2521665 has 16 divisors (see below), whose sum is σ = 4483200. Its totient is φ = 1344816.

The previous prime is 2521643. The next prime is 2521681. The reversal of 2521665 is 5661252.

It is not a de Polignac number, because 2521665 - 2⁷ = 2521537 is a prime.

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

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9205 + ... + 9474.

It is an arithmetic number, because the mean of its divisors is an integer number (280200).

2^2521665 is an apocalyptic number.

It is an amenable number.

2521665 is a deficient number, since it is larger than the sum of its proper divisors (1961535).

2521665 is a wasteful number, since it uses less digits than its factorization.

2521665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18693 (or 18687 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 2521665 is about 1587.9751257498. The cubic root of 2521665 is about 136.1118061266. Note that the first 3 decimals are identical.

It can be divided in two parts, 25216 and 65, that added together give a square (25281 = 159²).

The spelling of 2521665 in words is "two million, five hundred twenty-one thousand, six hundred sixty-five".