138998638 has 4 divisors (see below), whose sum is σ = 208497960. Its totient is φ = 69499318.

The previous prime is 138998633. The next prime is 138998659. The reversal of 138998638 is 836899831.

It is a happy number.

138998638 is digitally balanced in base 2 and base 3, because in such bases 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 an emirpimes, since its reverse is a distinct semiprime: 836899831 = 41 ⋅20412191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138998633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34749658 + ... + 34749661.

It is an arithmetic number, because the mean of its divisors is an integer number (52124490).

Almost surely, 2^138998638 is an apocalyptic number.

138998638 is a deficient number, since it is larger than the sum of its proper divisors (69499322).

138998638 is an equidigital number, since it uses as much as digits as its factorization.

138998638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69499321.

The product of its digits is 2239488, while the sum is 55.

The square root of 138998638 is about 11789.7683607440. The cubic root of 138998638 is about 518.0084548145.

The spelling of 138998638 in words is "one hundred thirty-eight million, nine hundred ninety-eight thousand, six hundred thirty-eight".