138997429 has 4 divisors (see below), whose sum is σ = 141620076. Its totient is φ = 136374784.

The previous prime is 138997409. The next prime is 138997433. The reversal of 138997429 is 924799831.

It is a happy number.

138997429 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.

It can be written as a sum of positive squares in 2 ways, for example, as 68856804 + 70140625 = 8298^2 + 8375^2 .

It is a cyclic number.

It is not a de Polignac number, because 138997429 - 2⁹ = 138996917 is a prime.

It is a super-2 number, since 2×138997429² = 38640570537220082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138997409) 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, 1311244 + ... + 1311349.

It is an arithmetic number, because the mean of its divisors is an integer number (35405019).

Almost surely, 2^138997429 is an apocalyptic number.

It is an amenable number.

138997429 is a deficient number, since it is larger than the sum of its proper divisors (2622647).

138997429 is an equidigital number, since it uses as much as digits as its factorization.

138997429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2622646.

The product of its digits is 979776, while the sum is 52.

The square root of 138997429 is about 11789.7170873605. The cubic root of 138997429 is about 518.0069529435.

The spelling of 138997429 in words is "one hundred thirty-eight million, nine hundred ninety-seven thousand, four hundred twenty-nine".