181042721 has 4 divisors (see below), whose sum is σ = 181168944. Its totient is φ = 180916500.

The previous prime is 181042711. The next prime is 181042727. The reversal of 181042721 is 127240181.

181042721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 127240181 = 179 ⋅710839.

It is a cyclic number.

It is not a de Polignac number, because 181042721 - 2⁶ = 181042657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (181042727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60935 + ... + 63836.

It is an arithmetic number, because the mean of its divisors is an integer number (45292236).

Almost surely, 2^181042721 is an apocalyptic number.

It is an amenable number.

181042721 is a deficient number, since it is larger than the sum of its proper divisors (126223).

181042721 is a wasteful number, since it uses less digits than its factorization.

181042721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126222.

The product of its (nonzero) digits is 896, while the sum is 26.

The square root of 181042721 is about 13455.2116668598. The cubic root of 181042721 is about 565.7097832923.

The spelling of 181042721 in words is "one hundred eighty-one million, forty-two thousand, seven hundred twenty-one".