2566117721 has 16 divisors (see below), whose sum is σ = 2724180480. Its totient is φ = 2412944640.

The previous prime is 2566117711. The next prime is 2566117769. The reversal of 2566117721 is 1277116652.

It is not a de Polignac number, because 2566117721 - 2⁶ = 2566117657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2566117711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1443185 + ... + 1444961.

It is an arithmetic number, because the mean of its divisors is an integer number (170261280).

Almost surely, 2^2566117721 is an apocalyptic number.

It is an amenable number.

2566117721 is a deficient number, since it is larger than the sum of its proper divisors (158062759).

2566117721 is a wasteful number, since it uses less digits than its factorization.

2566117721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3104.

The product of its digits is 35280, while the sum is 38.

The square root of 2566117721 is about 50656.8625262165. The cubic root of 2566117721 is about 1369.0695941825.

The spelling of 2566117721 in words is "two billion, five hundred sixty-six million, one hundred seventeen thousand, seven hundred twenty-one".