181005491 has 2 divisors, whose sum is σ = 181005492. Its totient is φ = 181005490.

The previous prime is 181005481. The next prime is 181005521. The reversal of 181005491 is 194500181.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 181005491 - 2⁶ = 181005427 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (181005481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90502745 + 90502746.

It is an arithmetic number, because the mean of its divisors is an integer number (90502746).

Almost surely, 2^181005491 is an apocalyptic number.

181005491 is a deficient number, since it is larger than the sum of its proper divisors (1).

181005491 is an equidigital number, since it uses as much as digits as its factorization.

181005491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1440, while the sum is 29.

The square root of 181005491 is about 13453.8281169339. The cubic root of 181005491 is about 565.6710027235.

The spelling of 181005491 in words is "one hundred eighty-one million, five thousand, four hundred ninety-one".