181340557281 has 81 divisors (see below), whose sum is σ = 289981170297. Its totient is φ = 109151565120.

The previous prime is 181340557273. The next prime is 181340557289. The reversal of 181340557281 is 182755043181.

The square root of 181340557281 is 425841.

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

181340557281 is a `hidden beast` number, since 1 + 8 + 13 + 4 + 0 + 557 + 2 + 81 = 666.

It is an interprime number because it is at equal distance from previous prime (181340557273) and next prime (181340557289).

It can be written as a sum of positive squares in 4 ways, for example, as 127523981025 + 53816576256 = 357105^2 + 231984^2 .

It is not a de Polignac number, because 181340557281 - 2³ = 181340557273 is a prime.

It is a super-2 number, since 2×181340557281² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (181340557289) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1013075650 + ... + 1013075828.

Almost surely, 2^181340557281 is an apocalyptic number.

181340557281 is the 425841-st square number.

181340557281 is the 212921-st centered octagonal number.

It is an amenable number.

181340557281 is a deficient number, since it is larger than the sum of its proper divisors (108640613016).

181340557281 is an equidigital number, since it uses as much as digits as its factorization.

181340557281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 512 (or 256 counting only the distinct ones).

The product of its (nonzero) digits is 268800, while the sum is 45.

The spelling of 181340557281 in words is "one hundred eighty-one billion, three hundred forty million, five hundred fifty-seven thousand, two hundred eighty-one".