2661256512073 has 2 divisors, whose sum is σ = 2661256512074. Its totient is φ = 2661256512072.

The previous prime is 2661256512071. The next prime is 2661256512127. The reversal of 2661256512073 is 3702156521662.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2478836122624 + 182420389449 = 1574432^2 + 427107^2 .

It is a cyclic number.

It is not a de Polignac number, because 2661256512073 - 2¹ = 2661256512071 is a prime.

It is a super-3 number, since 3×2661256512073³ (a number of 38 digits) contains 333 as substring.

Together with 2661256512071, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (2661256512071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1330628256036 + 1330628256037.

It is an arithmetic number, because the mean of its divisors is an integer number (1330628256037).

Almost surely, 2^{2661256512073} is an apocalyptic number.

It is an amenable number.

2661256512073 is a deficient number, since it is larger than the sum of its proper divisors (1).

2661256512073 is an equidigital number, since it uses as much as digits as its factorization.

2661256512073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 907200, while the sum is 46.

The spelling of 2661256512073 in words is "two trillion, six hundred sixty-one billion, two hundred fifty-six million, five hundred twelve thousand, seventy-three".