66401238 has 64 divisors (see below), whose sum is σ = 144921600. Its totient is φ = 20217600.

The previous prime is 66401227. The next prime is 66401239. The reversal of 66401238 is 83210466.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66401239) 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 31 ways as a sum of consecutive naturals, for example, 657388 + ... + 657488.

It is an arithmetic number, because the mean of its divisors is an integer number (2264400).

Almost surely, 2^66401238 is an apocalyptic number.

66401238 is an abundant number, since it is smaller than the sum of its proper divisors (78520362).

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

66401238 is a wasteful number, since it uses less digits than its factorization.

66401238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 66401238 is about 8148.6954784186. The cubic root of 66401238 is about 404.9412870230.

The spelling of 66401238 in words is "sixty-six million, four hundred one thousand, two hundred thirty-eight".