138777408 has 336 divisors, whose sum is σ = 521208000. Its totient is φ = 35804160.

The previous prime is 138777403. The next prime is 138777437. The reversal of 138777408 is 804777831.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (336).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138777403) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 931318 + ... + 931466.

Almost surely, 2^138777408 is an apocalyptic number.

138777408 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 138777408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (260604000).

138777408 is an abundant number, since it is smaller than the sum of its proper divisors (382430592).

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

138777408 is a wasteful number, since it uses less digits than its factorization.

138777408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195 (or 172 counting only the distinct ones).

The product of its (nonzero) digits is 263424, while the sum is 45.

The square root of 138777408 is about 11780.3823367495. The cubic root of 138777408 is about 517.7334884204.

The spelling of 138777408 in words is "one hundred thirty-eight million, seven hundred seventy-seven thousand, four hundred eight".