138958817805 has 24 divisors (see below), whose sum is σ = 241861396920. Its totient is φ = 73803847680.

The previous prime is 138958817801. The next prime is 138958817807. The reversal of 138958817805 is 508718859831.

138958817805 is a `hidden beast` number, since 1 + 38 + 9 + 588 + 17 + 8 + 0 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 25226651241 + 113732166564 = 158829^2 + 337242^2 .

It is not a de Polignac number, because 138958817805 - 2² = 138958817801 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138958817801) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6395740 + ... + 6417429.

It is an arithmetic number, because the mean of its divisors is an integer number (10077558205).

Almost surely, 2^138958817805 is an apocalyptic number.

138958817805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

138958817805 is a deficient number, since it is larger than the sum of its proper divisors (102902579115).

138958817805 is a wasteful number, since it uses less digits than its factorization.

138958817805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12813421 (or 12813418 counting only the distinct ones).

The product of its (nonzero) digits is 19353600, while the sum is 63.

The spelling of 138958817805 in words is "one hundred thirty-eight billion, nine hundred fifty-eight million, eight hundred seventeen thousand, eight hundred five".