138858660 has 36 divisors (see below), whose sum is σ = 421205148. Its totient is φ = 37028928.

The previous prime is 138858647. The next prime is 138858661. The reversal of 138858660 is 66858831.

138858660 is a `hidden beast` number, since 1 + 3 + 8 + 8 + 586 + 60 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 57426084 + 81432576 = 7578^2 + 9024^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (138858661) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 385539 + ... + 385898.

It is an arithmetic number, because the mean of its divisors is an integer number (11700143).

Almost surely, 2^138858660 is an apocalyptic number.

138858660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138858660 is an abundant number, since it is smaller than the sum of its proper divisors (282346488).

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

138858660 is a wasteful number, since it uses less digits than its factorization.

138858660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 771452 (or 771447 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 138858660 is about 11783.8304468454. The cubic root of 138858660 is about 517.8345103251.

The spelling of 138858660 in words is "one hundred thirty-eight million, eight hundred fifty-eight thousand, six hundred sixty".