2661554609281 has 4 divisors (see below), whose sum is σ = 2667111091200. Its totient is φ = 2655998127364.

The previous prime is 2661554609251. The next prime is 2661554609291. The reversal of 2661554609281 is 1829064551662.

It is a happy number.

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 cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2661554609281 is a prime.

It is a super-3 number, since 3×2661554609281³ (a number of 38 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2661554609251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2778240241 + ... + 2778241198.

It is an arithmetic number, because the mean of its divisors is an integer number (666777772800).

Almost surely, 2^{2661554609281} is an apocalyptic number.

It is an amenable number.

2661554609281 is a deficient number, since it is larger than the sum of its proper divisors (5556481919).

2661554609281 is an equidigital number, since it uses as much as digits as its factorization.

2661554609281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5556481918.

The product of its (nonzero) digits is 6220800, while the sum is 55.

The spelling of 2661554609281 in words is "two trillion, six hundred sixty-one billion, five hundred fifty-four million, six hundred nine thousand, two hundred eighty-one".