66438 has 12 divisors (see below), whose sum is σ = 143988. Its totient is φ = 22140.

The previous prime is 66431. The next prime is 66449. The reversal of 66438 is 83466.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66431) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1828 + ... + 1863.

It is an arithmetic number, because the mean of its divisors is an integer number (11999).

2⁶⁶⁴³⁸ is an apocalyptic number.

66438 is an abundant number, since it is smaller than the sum of its proper divisors (77550).

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

66438 is a wasteful number, since it uses less digits than its factorization.

66438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3699 (or 3696 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 66438 is about 257.7556982881. The cubic root of 66438 is about 40.5016003026.

The spelling of 66438 in words is "sixty-six thousand, four hundred thirty-eight".