131851638 has 40 divisors (see below), whose sum is σ = 301748832. Its totient is φ = 43012944.

The previous prime is 131851633. The next prime is 131851669. The reversal of 131851638 is 836158131.

131851638 is a `hidden beast` number, since 1 + 3 + 18 + 5 + 1 + 638 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131851633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1045 + ... + 16272.

Almost surely, 2^131851638 is an apocalyptic number.

131851638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 131851638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150874416).

131851638 is an abundant number, since it is smaller than the sum of its proper divisors (169897194).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

131851638 is a wasteful number, since it uses less digits than its factorization.

131851638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17378 (or 17369 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 131851638 is about 11482.6668505187. Note that the first 3 decimals coincide. The cubic root of 131851638 is about 508.9735062628.

The spelling of 131851638 in words is "one hundred thirty-one million, eight hundred fifty-one thousand, six hundred thirty-eight".