138641780 has 12 divisors (see below), whose sum is σ = 291147780. Its totient is φ = 55456704.

The previous prime is 138641773. The next prime is 138641843. The reversal of 138641780 is 87146831.

It can be written as a sum of positive squares in 2 ways, for example, as 42562576 + 96079204 = 6524^2 + 9802^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3466025 + ... + 3466064.

It is an arithmetic number, because the mean of its divisors is an integer number (24262315).

Almost surely, 2^138641780 is an apocalyptic number.

138641780 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138641780 is an abundant number, since it is smaller than the sum of its proper divisors (152506000).

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

138641780 is a wasteful number, since it uses less digits than its factorization.

138641780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6932098 (or 6932096 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 138641780 is about 11774.6244101457. The cubic root of 138641780 is about 517.5647720897.

The spelling of 138641780 in words is "one hundred thirty-eight million, six hundred forty-one thousand, seven hundred eighty".