138901261 has 4 divisors (see below), whose sum is σ = 140804092. Its totient is φ = 136998432.

The previous prime is 138901253. The next prime is 138901283. The reversal of 138901261 is 162109831.

138901261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 162109831 = 13 ⋅12469987.

It can be written as a sum of positive squares in 2 ways, for example, as 92525161 + 46376100 = 9619^2 + 6810^2 .

It is a cyclic number.

It is not a de Polignac number, because 138901261 - 2³ = 138901253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138901201) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 951306 + ... + 951451.

It is an arithmetic number, because the mean of its divisors is an integer number (35201023).

Almost surely, 2^138901261 is an apocalyptic number.

It is an amenable number.

138901261 is a deficient number, since it is larger than the sum of its proper divisors (1902831).

138901261 is an equidigital number, since it uses as much as digits as its factorization.

138901261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1902830.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 138901261 is about 11785.6379123067. The cubic root of 138901261 is about 517.8874610794.

It can be divided in two parts, 13890 and 1261, that added together give a palindrome (15151).

The spelling of 138901261 in words is "one hundred thirty-eight million, nine hundred one thousand, two hundred sixty-one".