2521225661 has 4 divisors (see below), whose sum is σ = 2630844192. Its totient is φ = 2411607132.

The previous prime is 2521225643. The next prime is 2521225687. The reversal of 2521225661 is 1665221252.

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 de Polignac number, because none of the positive numbers 2^k-2521225661 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 (2521225061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54809231 + ... + 54809276.

It is an arithmetic number, because the mean of its divisors is an integer number (657711048).

Almost surely, 2^2521225661 is an apocalyptic number.

It is an amenable number.

2521225661 is a deficient number, since it is larger than the sum of its proper divisors (109618531).

2521225661 is a wasteful number, since it uses less digits than its factorization.

2521225661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109618530.

The product of its digits is 14400, while the sum is 32.

The square root of 2521225661 is about 50211.8079837801. The cubic root of 2521225661 is about 1361.0390093990.

The spelling of 2521225661 in words is "two billion, five hundred twenty-one million, two hundred twenty-five thousand, six hundred sixty-one".