2661605412121 has 2 divisors, whose sum is σ = 2661605412122. Its totient is φ = 2661605412120.

The previous prime is 2661605412113. The next prime is 2661605412157. The reversal of 2661605412121 is 1212145061662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2517156768025 + 144448644096 = 1586555^2 + 380064^2 .

It is a cyclic number.

It is not a de Polignac number, because 2661605412121 - 2³ = 2661605412113 is a prime.

It is not a weakly prime, because it can be changed into another prime (2661605472121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1330802706060 + 1330802706061.

It is an arithmetic number, because the mean of its divisors is an integer number (1330802706061).

Almost surely, 2^{2661605412121} is an apocalyptic number.

It is an amenable number.

2661605412121 is a deficient number, since it is larger than the sum of its proper divisors (1).

2661605412121 is an equidigital number, since it uses as much as digits as its factorization.

2661605412121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 37.

The spelling of 2661605412121 in words is "two trillion, six hundred sixty-one billion, six hundred five million, four hundred twelve thousand, one hundred twenty-one".