1812485721 has 12 divisors (see below), whose sum is σ = 2526289808. Its totient is φ = 1155786984.

The previous prime is 1812485713. The next prime is 1812485777. The reversal of 1812485721 is 1275842181.

It is not a de Polignac number, because 1812485721 - 2³ = 1812485713 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 1812485721.

It is not an unprimeable number, because it can be changed into a prime (1812485621) 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 11 ways as a sum of consecutive naturals, for example, 569455 + ... + 572628.

Almost surely, 2^1812485721 is an apocalyptic number.

It is an amenable number.

1812485721 is a deficient number, since it is larger than the sum of its proper divisors (713804087).

1812485721 is a wasteful number, since it uses less digits than its factorization.

1812485721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1142132 (or 1142109 counting only the distinct ones).

The product of its digits is 35840, while the sum is 39.

The square root of 1812485721 is about 42573.2982161354. The cubic root of 1812485721 is about 1219.2465384821.

The spelling of 1812485721 in words is "one billion, eight hundred twelve million, four hundred eighty-five thousand, seven hundred twenty-one".