2661663121 has 4 divisors (see below), whose sum is σ = 2866406452. Its totient is φ = 2456919792.

The previous prime is 2661663113. The next prime is 2661663143. The reversal of 2661663121 is 1213661662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1213661662 = 2 ⋅606830831.

It can be written as a sum of positive squares in 2 ways, for example, as 1090650625 + 1571012496 = 33025^2 + 39636^2 .

It is a cyclic number.

It is not a de Polignac number, because 2661663121 - 2³ = 2661663113 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2661660121) 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, 102371646 + ... + 102371671.

It is an arithmetic number, because the mean of its divisors is an integer number (716601613).

Almost surely, 2^2661663121 is an apocalyptic number.

It is an amenable number.

2661663121 is a deficient number, since it is larger than the sum of its proper divisors (204743331).

2661663121 is a wasteful number, since it uses less digits than its factorization.

2661663121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204743330.

The product of its digits is 15552, while the sum is 34.

The square root of 2661663121 is about 51591.3085800312. The cubic root of 2661663121 is about 1385.8546894781.

The spelling of 2661663121 in words is "two billion, six hundred sixty-one million, six hundred sixty-three thousand, one hundred twenty-one".