138600020 has 24 divisors (see below), whose sum is σ = 313449864. Its totient is φ = 51175296.

The previous prime is 138600017. The next prime is 138600043. The reversal of 138600020 is 20006831.

It can be written as a sum of positive squares in 4 ways, for example, as 11316496 + 127283524 = 3364^2 + 11282^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 138599965 and 138600001.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 266279 + ... + 266798.

It is an arithmetic number, because the mean of its divisors is an integer number (13060411).

Almost surely, 2^138600020 is an apocalyptic number.

138600020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138600020 is an abundant number, since it is smaller than the sum of its proper divisors (174849844).

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

138600020 is a wasteful number, since it uses less digits than its factorization.

138600020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 533099 (or 533097 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 138600020 is about 11772.8509716211. The cubic root of 138600020 is about 517.5128020046.

Adding to 138600020 its reverse (20006831), we get a palindrome (158606851).

The spelling of 138600020 in words is "one hundred thirty-eight million, six hundred thousand, twenty".