18531521812 has 12 divisors (see below), whose sum is σ = 32438975296. Its totient is φ = 9263243160.

The previous prime is 18531521791. The next prime is 18531521821. The reversal of 18531521812 is 21812513581.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 612828 + ... + 642355.

Almost surely, 2^18531521812 is an apocalyptic number.

It is an amenable number.

18531521812 is a deficient number, since it is larger than the sum of its proper divisors (13907453484).

18531521812 is a wasteful number, since it uses less digits than its factorization.

18531521812 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1258878 (or 1258876 counting only the distinct ones).

The product of its digits is 19200, while the sum is 37.

The spelling of 18531521812 in words is "eighteen billion, five hundred thirty-one million, five hundred twenty-one thousand, eight hundred twelve".