181090521 has 6 divisors (see below), whose sum is σ = 261575210. Its totient is φ = 120727008.

The previous prime is 181090513. The next prime is 181090537. The reversal of 181090521 is 125090181.

It can be written as a sum of positive squares in only one way, i.e., 134304921 + 46785600 = 11589^2 + 6840^2 .

It is not a de Polignac number, because 181090521 - 2³ = 181090513 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181090421) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 10060576 + ... + 10060593.

Almost surely, 2^181090521 is an apocalyptic number.

It is an amenable number.

181090521 is a deficient number, since it is larger than the sum of its proper divisors (80484689).

181090521 is a wasteful number, since it uses less digits than its factorization.

181090521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20121175 (or 20121172 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 181090521 is about 13456.9878130286. The cubic root of 181090521 is about 565.7595662901.

The spelling of 181090521 in words is "one hundred eighty-one million, ninety thousand, five hundred twenty-one".