2666520121 has 4 divisors (see below), whose sum is σ = 2667165732. Its totient is φ = 2665874512.

The previous prime is 2666520119. The next prime is 2666520133. The reversal of 2666520121 is 1210256662.

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 1733889600 + 932630521 = 41640^2 + 30539^2 .

It is a cyclic number.

It is not a de Polignac number, because 2666520121 - 2¹ = 2666520119 is a prime.

It is a super-2 number, since 2×2666520121² = 14220659111395709282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2666520161) 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, 316570 + ... + 324883.

It is an arithmetic number, because the mean of its divisors is an integer number (666791433).

Almost surely, 2^2666520121 is an apocalyptic number.

It is an amenable number.

2666520121 is a deficient number, since it is larger than the sum of its proper divisors (645611).

2666520121 is an equidigital number, since it uses as much as digits as its factorization.

2666520121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645610.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 2666520121 is about 51638.3590076215. The cubic root of 2666520121 is about 1386.6971459634.

Adding to 2666520121 its reverse (1210256662), we get a palindrome (3876776783).

The spelling of 2666520121 in words is "two billion, six hundred sixty-six million, five hundred twenty thousand, one hundred twenty-one".