18512051481 has 243 divisors, whose sum is σ = 37285852149. Its totient is φ = 8816623200.

The previous prime is 18512051473. The next prime is 18512051483. The reversal of 18512051481 is 18415021581.

The square root of 18512051481 is 136059.

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

18512051481 is a `hidden beast` number, since 1 + 8 + 5 + 120 + 51 + 481 = 666.

It is not a de Polignac number, because 18512051481 - 2³ = 18512051473 is a prime.

It is a super-2 number, since 2×18512051481² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18512051483) by changing a digit.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 597162936 + ... + 597162966.

Almost surely, 2^18512051481 is an apocalyptic number.

18512051481 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18512051481 is the 136059-th square number.

18512051481 is the 68030-th centered octagonal number.

It is an amenable number.

18512051481 is an abundant number, since it is smaller than the sum of its proper divisors (18773800668).

18512051481 is a wasteful number, since it uses less digits than its factorization.

18512051481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 12800, while the sum is 36.

Multiplying 18512051481 by its sum of digits (36), we get a square (666433853316 = 816354²).

The spelling of 18512051481 in words is "eighteen billion, five hundred twelve million, fifty-one thousand, four hundred eighty-one".