261552373055161 has 2 divisors, whose sum is σ = 261552373055162. Its totient is φ = 261552373055160.

The previous prime is 261552373055147. The next prime is 261552373055173. The reversal of 261552373055161 is 161550373255162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 191846572055161 + 69705801000000 = 13850869^2 + 8349000^2 .

It is a cyclic number.

It is not a de Polignac number, because 261552373055161 - 2¹³ = 261552373046969 is a prime.

It is a super-2 number, since 2×261552373055161² (a number of 30 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 261552373055099 and 261552373055108.

It is not a weakly prime, because it can be changed into another prime (261552371055161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130776186527580 + 130776186527581.

It is an arithmetic number, because the mean of its divisors is an integer number (130776186527581).

Almost surely, 2^{261552373055161} is an apocalyptic number.

It is an amenable number.

261552373055161 is a deficient number, since it is larger than the sum of its proper divisors (1).

261552373055161 is an equidigital number, since it uses as much as digits as its factorization.

261552373055161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5670000, while the sum is 52.

The spelling of 261552373055161 in words is "two hundred sixty-one trillion, five hundred fifty-two billion, three hundred seventy-three million, fifty-five thousand, one hundred sixty-one".