138409308 has 72 divisors (see below), whose sum is σ = 386594208. Its totient is φ = 41530368.

The previous prime is 138409307. The next prime is 138409309. The reversal of 138409308 is 803904831.

It is an interprime number because it is at equal distance from previous prime (138409307) and next prime (138409309).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138409301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9160 + ... + 18992.

It is an arithmetic number, because the mean of its divisors is an integer number (5369364).

Almost surely, 2^138409308 is an apocalyptic number.

138409308 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138409308, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (193297104).

138409308 is an abundant number, since it is smaller than the sum of its proper divisors (248184900).

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

138409308 is a wasteful number, since it uses less digits than its factorization.

138409308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9883 (or 9878 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 138409308 is about 11764.7485310992. The cubic root of 138409308 is about 517.2753292052.

The spelling of 138409308 in words is "one hundred thirty-eight million, four hundred nine thousand, three hundred eight".