138401280 has 120 divisors (see below), whose sum is σ = 479402352. Its totient is φ = 36900864.

The previous prime is 138401279. The next prime is 138401287. The reversal of 138401280 is 82104831.

138401280 is a `hidden beast` number, since 1 + 384 + 0 + 1 + 280 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138401287) 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, 20037 + ... + 26043.

Almost surely, 2^138401280 is an apocalyptic number.

138401280 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 138401280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239701176).

138401280 is an abundant number, since it is smaller than the sum of its proper divisors (341001072).

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

138401280 is an equidigital number, since it uses as much as digits as its factorization.

138401280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6036 (or 6017 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 138401280 is about 11764.4073373885. The cubic root of 138401280 is about 517.2653280314.

The spelling of 138401280 in words is "one hundred thirty-eight million, four hundred one thousand, two hundred eighty".