138545261 has 4 divisors (see below), whose sum is σ = 144568992. Its totient is φ = 132521532.

The previous prime is 138545171. The next prime is 138545287. The reversal of 138545261 is 162545831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 162545831 = 7 ⋅23220833.

It is a cyclic number.

It is not a de Polignac number, because 138545261 - 2¹⁴ = 138528877 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 (138545161) 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, 3011831 + ... + 3011876.

It is an arithmetic number, because the mean of its divisors is an integer number (36142248).

Almost surely, 2^138545261 is an apocalyptic number.

It is an amenable number.

138545261 is a deficient number, since it is larger than the sum of its proper divisors (6023731).

138545261 is an equidigital number, since it uses as much as digits as its factorization.

138545261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6023730.

The product of its digits is 28800, while the sum is 35.

The square root of 138545261 is about 11770.5250944892. The cubic root of 138545261 is about 517.4446389159. Note that the first 3 decimals are identical.

The spelling of 138545261 in words is "one hundred thirty-eight million, five hundred forty-five thousand, two hundred sixty-one".