181855338025 has 81 divisors (see below), whose sum is σ = 249533008621. Its totient is φ = 131440583680.

The previous prime is 181855338013. The next prime is 181855338079. The reversal of 181855338025 is 520833558181.

It is a happy number.

The square root of 181855338025 is 426445.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 40 ways, for example, as 113840784409 + 68014553616 = 337403^2 + 260796^2 .

It is not a de Polignac number, because 181855338025 - 2⁷ = 181855337897 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 181855338025.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 1051186839 + ... + 1051187011.

Almost surely, 2^181855338025 is an apocalyptic number.

181855338025 is the 426445-th square number.

181855338025 is the 213223-rd centered octagonal number.

It is an amenable number.

181855338025 is a deficient number, since it is larger than the sum of its proper divisors (67677670596).

181855338025 is an equidigital number, since it uses as much as digits as its factorization.

181855338025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448 (or 224 counting only the distinct ones).

The product of its (nonzero) digits is 1152000, while the sum is 49.

Multiplying 181855338025 by its sum of digits (49), we get a square (8910911563225 = 2985115²).

The spelling of 181855338025 in words is "one hundred eighty-one billion, eight hundred fifty-five million, three hundred thirty-eight thousand, twenty-five".