2661345652061 has 2 divisors, whose sum is σ = 2661345652062. Its totient is φ = 2661345652060.

The previous prime is 2661345651917. The next prime is 2661345652081. The reversal of 2661345652061 is 1602565431662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1969795408036 + 691550244025 = 1403494^2 + 831595^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2661345652061 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2661345651997 and 2661345652015.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2661345652081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1330672826030 + 1330672826031.

It is an arithmetic number, because the mean of its divisors is an integer number (1330672826031).

Almost surely, 2^{2661345652061} is an apocalyptic number.

It is an amenable number.

2661345652061 is a deficient number, since it is larger than the sum of its proper divisors (1).

2661345652061 is an equidigital number, since it uses as much as digits as its factorization.

2661345652061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1555200, while the sum is 47.

It can be divided in two parts, 266134 and 5652061, that added together give a palindrome (5918195).

The spelling of 2661345652061 in words is "two trillion, six hundred sixty-one billion, three hundred forty-five million, six hundred fifty-two thousand, sixty-one".