66138198 has 32 divisors (see below), whose sum is σ = 152596224. Its totient is φ = 18718752.

The previous prime is 66138197. The next prime is 66138209. The reversal of 66138198 is 89183166.

66138198 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×66138198² = 8748522469374408, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66138197) 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 15 ways as a sum of consecutive naturals, for example, 2865 + ... + 11852.

It is an arithmetic number, because the mean of its divisors is an integer number (4768632).

Almost surely, 2^66138198 is an apocalyptic number.

66138198 is an abundant number, since it is smaller than the sum of its proper divisors (86458026).

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

66138198 is a wasteful number, since it uses less digits than its factorization.

66138198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14836.

The product of its digits is 62208, while the sum is 42.

The square root of 66138198 is about 8132.5394557912. The cubic root of 66138198 is about 404.4058717244.

The spelling of 66138198 in words is "sixty-six million, one hundred thirty-eight thousand, one hundred ninety-eight".