138640284 has 36 divisors (see below), whose sum is σ = 354397680. Its totient is φ = 45693120.

The previous prime is 138640273. The next prime is 138640289. The reversal of 138640284 is 482046831.

138640284 is a `hidden beast` number, since 1 + 3 + 8 + 640 + 2 + 8 + 4 = 666.

138640284 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a super-2 number, since 2×138640284² = 38442256695201312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138640289) 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, 18432 + ... + 24839.

It is an arithmetic number, because the mean of its divisors is an integer number (9844380).

Almost surely, 2^138640284 is an apocalyptic number.

It is an amenable number.

138640284 is an abundant number, since it is smaller than the sum of its proper divisors (215757396).

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

138640284 is a wasteful number, since it uses less digits than its factorization.

138640284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43370 (or 43365 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 36.

The square root of 138640284 is about 11774.5608835319. The cubic root of 138640284 is about 517.5629105063.

The spelling of 138640284 in words is "one hundred thirty-eight million, six hundred forty thousand, two hundred eighty-four".