138511261 has 4 divisors (see below), whose sum is σ = 158298592. Its totient is φ = 118723932.

The previous prime is 138511231. The next prime is 138511271. The reversal of 138511261 is 162115831.

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.

It is a cyclic number.

It is not a de Polignac number, because 138511261 - 2⁷ = 138511133 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 (138511201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9893655 + ... + 9893668.

It is an arithmetic number, because the mean of its divisors is an integer number (39574648).

Almost surely, 2^138511261 is an apocalyptic number.

It is an amenable number.

138511261 is a deficient number, since it is larger than the sum of its proper divisors (19787331).

138511261 is an equidigital number, since it uses as much as digits as its factorization.

138511261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19787330.

The product of its digits is 1440, while the sum is 28.

The square root of 138511261 is about 11769.0807202602. The cubic root of 138511261 is about 517.4023072452.

The spelling of 138511261 in words is "one hundred thirty-eight million, five hundred eleven thousand, two hundred sixty-one".