138378261 has 16 divisors (see below), whose sum is σ = 216562304. Its totient is φ = 76935744.

The previous prime is 138378259. The next prime is 138378271. The reversal of 138378261 is 162873831.

It is not a de Polignac number, because 138378261 - 2¹ = 138378259 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138378211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 88270 + ... + 89823.

It is an arithmetic number, because the mean of its divisors is an integer number (13535144).

Almost surely, 2^138378261 is an apocalyptic number.

It is an amenable number.

138378261 is a deficient number, since it is larger than the sum of its proper divisors (78184043).

138378261 is a wasteful number, since it uses less digits than its factorization.

138378261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178140.

The product of its digits is 48384, while the sum is 39.

The square root of 138378261 is about 11763.4289643794. The cubic root of 138378261 is about 517.2366491281.

The spelling of 138378261 in words is "one hundred thirty-eight million, three hundred seventy-eight thousand, two hundred sixty-one".