138664 has 8 divisors (see below), whose sum is σ = 260010. Its totient is φ = 69328.

The previous prime is 138661. The next prime is 138679. The reversal of 138664 is 466831.

It can be written as a sum of positive squares in only one way, i.e., 136900 + 1764 = 370^2 + 42^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (138661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8659 + ... + 8674.

2¹³⁸⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

138664 is a deficient number, since it is larger than the sum of its proper divisors (121346).

138664 is a wasteful number, since it uses less digits than its factorization.

138664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17339 (or 17335 counting only the distinct ones).

The product of its digits is 3456, while the sum is 28.

The square root of 138664 is about 372.3761539089. The cubic root of 138664 is about 51.7592420501.

The spelling of 138664 in words is "one hundred thirty-eight thousand, six hundred sixty-four".