138401780 has 48 divisors (see below), whose sum is σ = 319165056. Its totient is φ = 49994880.

The previous prime is 138401749. The next prime is 138401789. The reversal of 138401780 is 87104831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138401789) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32537 + ... + 36543.

It is an arithmetic number, because the mean of its divisors is an integer number (6649272).

Almost surely, 2^138401780 is an apocalyptic number.

138401780 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 138401780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (159582528).

138401780 is an abundant number, since it is smaller than the sum of its proper divisors (180763276).

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

138401780 is a wasteful number, since it uses less digits than its factorization.

138401780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4184 (or 4182 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 32.

The square root of 138401780 is about 11764.4285879086. The cubic root of 138401780 is about 517.2659509359.

The spelling of 138401780 in words is "one hundred thirty-eight million, four hundred one thousand, seven hundred eighty".