1812261521 has 24 divisors (see below), whose sum is σ = 2146905000. Its totient is φ = 1525058304.

The previous prime is 1812261511. The next prime is 1812261527. The reversal of 1812261521 is 1251622181.

It can be written as a sum of positive squares in 4 ways, for example, as 9834496 + 1802427025 = 3136^2 + 42455^2 .

It is not a de Polignac number, because 1812261521 - 2¹⁰ = 1812260497 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 (1812261527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 648395 + ... + 651183.

It is an arithmetic number, because the mean of its divisors is an integer number (89454375).

Almost surely, 2^1812261521 is an apocalyptic number.

It is an amenable number.

1812261521 is a deficient number, since it is larger than the sum of its proper divisors (334643479).

1812261521 is a wasteful number, since it uses less digits than its factorization.

1812261521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3041 (or 3034 counting only the distinct ones).

The product of its digits is 1920, while the sum is 29.

The square root of 1812261521 is about 42570.6650288670. The cubic root of 1812261521 is about 1219.1962638155.

The spelling of 1812261521 in words is "one billion, eight hundred twelve million, two hundred sixty-one thousand, five hundred twenty-one".