2491286581161 has 27 divisors (see below), whose sum is σ = 4186095052503. Its totient is φ = 1423573391520.

The previous prime is 2491286581151. The next prime is 2491286581237. The reversal of 2491286581161 is 1611856821942.

The square root of 2491286581161 is 1578381.

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

2491286581161 is a `hidden beast` number, since 2 + 49 + 1 + 2 + 8 + 6 + 581 + 16 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 850325581161 + 1640961000000 = 922131^2 + 1281000^2 .

It is not a de Polignac number, because 2491286581161 - 2¹⁹ = 2491286056873 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2491286581098 and 2491286581107.

It is not an unprimeable number, because it can be changed into a prime (2491286581111) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 33108421 + ... + 33183581.

Almost surely, 2^{2491286581161} is an apocalyptic number.

2491286581161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

2491286581161 is the 1578381-st square number.

2491286581161 is the 789191-st centered octagonal number.

It is an amenable number.

2491286581161 is a deficient number, since it is larger than the sum of its proper divisors (1694808471342).

2491286581161 is an frugal number, since it uses more digits than its factorization.

2491286581161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150342 (or 75171 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 54.

The spelling of 2491286581161 in words is "two trillion, four hundred ninety-one billion, two hundred eighty-six million, five hundred eighty-one thousand, one hundred sixty-one".