138691440 has 200 divisors, whose sum is σ = 510436080. Its totient is φ = 34781184.

The previous prime is 138691439. The next prime is 138691453. The reversal of 138691440 is 44196831.

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

It is a junction number, because it is equal to n+sod(n) for n = 138691395 and 138691404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 109531 + ... + 110789.

Almost surely, 2^138691440 is an apocalyptic number.

138691440 is a gapful number since it is divisible by the number (10) 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 138691440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (255218040).

138691440 is an abundant number, since it is smaller than the sum of its proper divisors (371744640).

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

138691440 is a wasteful number, since it uses less digits than its factorization.

138691440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1301 (or 1286 counting only the distinct ones).

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

The square root of 138691440 is about 11776.7329934919. The cubic root of 138691440 is about 517.6265600982.

The spelling of 138691440 in words is "one hundred thirty-eight million, six hundred ninety-one thousand, four hundred forty".