138820645440 has 672 divisors, whose sum is σ = 539203392000. Its totient is φ = 32572440576.

The previous prime is 138820645409. The next prime is 138820645499. The reversal of 138820645440 is 44546028831.

138820645440 is a `hidden beast` number, since 1 + 3 + 88 + 20 + 6 + 4 + 544 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 73488016 + ... + 73489904.

It is an arithmetic number, because the mean of its divisors is an integer number (802386000).

Almost surely, 2^138820645440 is an apocalyptic number.

138820645440 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 138820645440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (269601696000).

138820645440 is an abundant number, since it is smaller than the sum of its proper divisors (400382746560).

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

138820645440 is a wasteful number, since it uses less digits than its factorization.

138820645440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2027 (or 2014 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 45.

The spelling of 138820645440 in words is "one hundred thirty-eight billion, eight hundred twenty million, six hundred forty-five thousand, four hundred forty".