181905481 has 2 divisors, whose sum is σ = 181905482. Its totient is φ = 181905480.

The previous prime is 181905443. The next prime is 181905497. The reversal of 181905481 is 184509181.

181905481 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 178356025 + 3549456 = 13355^2 + 1884^2 .

It is an emirp because it is prime and its reverse (184509181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181905481 - 2¹⁷ = 181774409 is a prime.

It is a super-2 number, since 2×181905481² = 66179208035682722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 181905481.

It is not a weakly prime, because it can be changed into another prime (181905401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90952740 + 90952741.

It is an arithmetic number, because the mean of its divisors is an integer number (90952741).

Almost surely, 2^181905481 is an apocalyptic number.

It is an amenable number.

181905481 is a deficient number, since it is larger than the sum of its proper divisors (1).

181905481 is an equidigital number, since it uses as much as digits as its factorization.

181905481 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 37.

The square root of 181905481 is about 13487.2340010841. The cubic root of 181905481 is about 566.6069905246.

The spelling of 181905481 in words is "one hundred eighty-one million, nine hundred five thousand, four hundred eighty-one".