2521008661 has 4 divisors (see below), whose sum is σ = 2521110592. Its totient is φ = 2520906732.

The previous prime is 2521008649. The next prime is 2521008689. The reversal of 2521008661 is 1668001252.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2521008661 - 2²³ = 2512620053 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 (2521008631) 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, 12370 + ... + 72076.

It is an arithmetic number, because the mean of its divisors is an integer number (630277648).

Almost surely, 2^2521008661 is an apocalyptic number.

It is an amenable number.

2521008661 is a deficient number, since it is larger than the sum of its proper divisors (101931).

2521008661 is an equidigital number, since it uses as much as digits as its factorization.

2521008661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101930.

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 2521008661 is about 50209.6470909725. The cubic root of 2521008661 is about 1360.9999604100. Note that the first 4 decimals are identical.

The spelling of 2521008661 in words is "two billion, five hundred twenty-one million, eight thousand, six hundred sixty-one".