138995731 has 4 divisors (see below), whose sum is σ = 158852272. Its totient is φ = 119139192.

The previous prime is 138995713. The next prime is 138995743. The reversal of 138995731 is 137599831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 137599831 = 1423 ⋅96697.

It is a cyclic number.

It is not a de Polignac number, because 138995731 - 2¹⁷ = 138864659 is a prime.

It is a super-2 number, since 2×138995731² = 38639626472448722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138995761) 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, 9928260 + ... + 9928273.

It is an arithmetic number, because the mean of its divisors is an integer number (39713068).

Almost surely, 2^138995731 is an apocalyptic number.

138995731 is a deficient number, since it is larger than the sum of its proper divisors (19856541).

138995731 is an equidigital number, since it uses as much as digits as its factorization.

138995731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19856540.

The product of its digits is 204120, while the sum is 46.

The square root of 138995731 is about 11789.6450752345. The cubic root of 138995731 is about 518.0048436014.

The spelling of 138995731 in words is "one hundred thirty-eight million, nine hundred ninety-five thousand, seven hundred thirty-one".