2581774661 has 4 divisors (see below), whose sum is σ = 2581960524. Its totient is φ = 2581588800.

The previous prime is 2581774627. The next prime is 2581774691. The reversal of 2581774661 is 1664771852.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 343917025 + 2237857636 = 18545^2 + 47306^2 .

It is a cyclic number.

It is not a de Polignac number, because 2581774661 - 2⁶ = 2581774597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2581774621) 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, 70250 + ... + 100491.

It is an arithmetic number, because the mean of its divisors is an integer number (645490131).

Almost surely, 2^2581774661 is an apocalyptic number.

It is an amenable number.

2581774661 is a deficient number, since it is larger than the sum of its proper divisors (185863).

2581774661 is a wasteful number, since it uses less digits than its factorization.

2581774661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185862.

The product of its digits is 564480, while the sum is 47.

The square root of 2581774661 is about 50811.1666959144. The cubic root of 2581774661 is about 1371.8483692964.

The spelling of 2581774661 in words is "two billion, five hundred eighty-one million, seven hundred seventy-four thousand, six hundred sixty-one".