2106361671561 has 105 divisors (see below), whose sum is σ = 3687589748951. Its totient is φ = 1202538034656.

The previous prime is 2106361671559. The next prime is 2106361671569. The reversal of 2106361671561 is 1651761636012.

The square root of 2106361671561 is 1451331.

It is a perfect power (a square), and thus also a powerful number.

2106361671561 is a `hidden beast` number, since 2 + 1 + 0 + 6 + 3 + 6 + 16 + 71 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 599006342025 + 1507355329536 = 773955^2 + 1227744^2 .

It is not a de Polignac number, because 2106361671561 - 2¹ = 2106361671559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2106361671569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 104 ways as a sum of consecutive naturals, for example, 1920110365 + ... + 1920111461.

Almost surely, 2^{2106361671561} is an apocalyptic number.

2106361671561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

2106361671561 is the 1451331-st square number.

2106361671561 is the 725666-th centered octagonal number.

It is an amenable number.

2106361671561 is a deficient number, since it is larger than the sum of its proper divisors (1581228077390).

2106361671561 is an frugal number, since it uses more digits than its factorization.

2106361671561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2240 (or 1107 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The spelling of 2106361671561 in words is "two trillion, one hundred six billion, three hundred sixty-one million, six hundred seventy-one thousand, five hundred sixty-one".