138056381 has 4 divisors (see below), whose sum is σ = 140116992. Its totient is φ = 135995772.

The previous prime is 138056363. The next prime is 138056383. The reversal of 138056381 is 183650831.

138056381 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 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 138056381 - 2²² = 133862077 is a prime.

It is a super-2 number, since 2×138056381² = 38119128669634322, which contains 22 as substring.

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 (138056383) 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, 1030205 + ... + 1030338.

It is an arithmetic number, because the mean of its divisors is an integer number (35029248).

Almost surely, 2^138056381 is an apocalyptic number.

138056381 is the 6281-st centered heptagonal number.

It is an amenable number.

138056381 is a deficient number, since it is larger than the sum of its proper divisors (2060611).

138056381 is an equidigital number, since it uses as much as digits as its factorization.

138056381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2060610.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 138056381 is about 11749.7396141361. The cubic root of 138056381 is about 516.8352917974.

The spelling of 138056381 in words is "one hundred thirty-eight million, fifty-six thousand, three hundred eighty-one".