138721999284 has 108 divisors (see below), whose sum is σ = 385685574820. Its totient is φ = 42009580800.

The previous prime is 138721999271. The next prime is 138721999291. The reversal of 138721999284 is 482999127831.

138721999284 is a `hidden beast` number, since 1 + 387 + 2 + 1 + 99 + 92 + 84 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 46949355684 + 91772643600 = 216678^2 + 302940^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7260624 + ... + 7279704.

Almost surely, 2^138721999284 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138721999284, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (192842787410).

138721999284 is an abundant number, since it is smaller than the sum of its proper divisors (246963575536).

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

138721999284 is a wasteful number, since it uses less digits than its factorization.

138721999284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20782 (or 20766 counting only the distinct ones).

The product of its digits is 15676416, while the sum is 63.

The spelling of 138721999284 in words is "one hundred thirty-eight billion, seven hundred twenty-one million, nine hundred ninety-nine thousand, two hundred eighty-four".