138968261 has 16 divisors (see below), whose sum is σ = 152280000. Its totient is φ = 126314496.

The previous prime is 138968233. The next prime is 138968281. The reversal of 138968261 is 162869831.

It is a cyclic number.

It is not a de Polignac number, because 138968261 - 2⁶ = 138968197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138968281) 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, 97925 + ... + 99333.

It is an arithmetic number, because the mean of its divisors is an integer number (9517500).

Almost surely, 2^138968261 is an apocalyptic number.

It is an amenable number.

138968261 is a deficient number, since it is larger than the sum of its proper divisors (13311739).

138968261 is a wasteful number, since it uses less digits than its factorization.

138968261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1636.

The product of its digits is 124416, while the sum is 44.

The square root of 138968261 is about 11788.4800122832. The cubic root of 138968261 is about 517.9707165808.

The spelling of 138968261 in words is "one hundred thirty-eight million, nine hundred sixty-eight thousand, two hundred sixty-one".