181602725561 has 4 divisors (see below), whose sum is σ = 182277828900. Its totient is φ = 180927622224.

The previous prime is 181602725543. The next prime is 181602725581. The reversal of 181602725561 is 165527206181.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14112252025 + 167490473536 = 118795^2 + 409256^2 .

It is a cyclic number.

It is not a de Polignac number, because 181602725561 - 2⁶ = 181602725497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181602725581) 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, 337551266 + ... + 337551803.

It is an arithmetic number, because the mean of its divisors is an integer number (45569457225).

Almost surely, 2^181602725561 is an apocalyptic number.

It is an amenable number.

181602725561 is a deficient number, since it is larger than the sum of its proper divisors (675103339).

181602725561 is an equidigital number, since it uses as much as digits as its factorization.

181602725561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 675103338.

The product of its (nonzero) digits is 201600, while the sum is 44.

The spelling of 181602725561 in words is "one hundred eighty-one billion, six hundred two million, seven hundred twenty-five thousand, five hundred sixty-one".