138673998 has 64 divisors (see below), whose sum is σ = 337608000. Its totient is φ = 41997312.

The previous prime is 138673979. The next prime is 138674009. The reversal of 138673998 is 899376831.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24018 + ... + 29226.

It is an arithmetic number, because the mean of its divisors is an integer number (5275125).

Almost surely, 2^138673998 is an apocalyptic number.

138673998 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 138673998, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (168804000).

138673998 is an abundant number, since it is smaller than the sum of its proper divisors (198934002).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138673998 is a wasteful number, since it uses less digits than its factorization.

138673998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5266 (or 5260 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 54.

The square root of 138673998 is about 11775.9924422530. The cubic root of 138673998 is about 517.6048600784.

The spelling of 138673998 in words is "one hundred thirty-eight million, six hundred seventy-three thousand, nine hundred ninety-eight".