66158388 has 18 divisors (see below), whose sum is σ = 167233794. Its totient is φ = 22052784.

The previous prime is 66158383. The next prime is 66158401. The reversal of 66158388 is 88385166.

66158388 is a `hidden beast` number, since 6 + 61 + 583 + 8 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 50381604 + 15776784 = 7098^2 + 3972^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66158383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 918831 + ... + 918902.

Almost surely, 2^66158388 is an apocalyptic number.

It is an amenable number.

66158388 is an abundant number, since it is smaller than the sum of its proper divisors (101075406).

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

66158388 is a wasteful number, since it uses less digits than its factorization.

66158388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1837743 (or 1837738 counting only the distinct ones).

The product of its digits is 276480, while the sum is 45.

The square root of 66158388 is about 8133.7806707582. The cubic root of 66158388 is about 404.4470185156.

It can be divided in two parts, 661 and 58388, that added together give a 10-th power (59049 = 3¹⁰).

The spelling of 66158388 in words is "sixty-six million, one hundred fifty-eight thousand, three hundred eighty-eight".