181151521 has 2 divisors, whose sum is σ = 181151522. Its totient is φ = 181151520.

The previous prime is 181151501. The next prime is 181151533. The reversal of 181151521 is 125151181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 109495296 + 71656225 = 10464^2 + 8465^2 .

It is an emirp because it is prime and its reverse (125151181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181151521 - 2¹¹ = 181149473 is a prime.

It is a super-2 number, since 2×181151521² = 65631747121226882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (181151501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90575760 + 90575761.

It is an arithmetic number, because the mean of its divisors is an integer number (90575761).

Almost surely, 2^181151521 is an apocalyptic number.

It is an amenable number.

181151521 is a deficient number, since it is larger than the sum of its proper divisors (1).

181151521 is an equidigital number, since it uses as much as digits as its factorization.

181151521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 400, while the sum is 25.

The square root of 181151521 is about 13459.2541026611. The cubic root of 181151521 is about 565.8230841725.

The spelling of 181151521 in words is "one hundred eighty-one million, one hundred fifty-one thousand, five hundred twenty-one".