138137868 has 36 divisors (see below), whose sum is σ = 380926728. Its totient is φ = 41859840.

The previous prime is 138137861. The next prime is 138137873. The reversal of 138137868 is 868731831.

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (138137861) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 174021 + ... + 174812.

It is an arithmetic number, because the mean of its divisors is an integer number (10581298).

Almost surely, 2^138137868 is an apocalyptic number.

138137868 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

138137868 is an abundant number, since it is smaller than the sum of its proper divisors (242788860).

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

138137868 is a wasteful number, since it uses less digits than its factorization.

138137868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 348854 (or 348849 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 138137868 is about 11753.2067113618. The cubic root of 138137868 is about 516.9369581691.

The spelling of 138137868 in words is "one hundred thirty-eight million, one hundred thirty-seven thousand, eight hundred sixty-eight".