138668436 has 72 divisors (see below), whose sum is σ = 365994720. Its totient is φ = 45906912.

The previous prime is 138668429. The next prime is 138668461. The reversal of 138668436 is 634866831.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 138668391 and 138668400.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 173590 + ... + 174386.

It is an arithmetic number, because the mean of its divisors is an integer number (5083260).

Almost surely, 2^138668436 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 138668436, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (182997360).

138668436 is an abundant number, since it is smaller than the sum of its proper divisors (227326284).

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

138668436 is a wasteful number, since it uses less digits than its factorization.

138668436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995 (or 981 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

The square root of 138668436 is about 11775.7562814454. The cubic root of 138668436 is about 517.5979398752.

The spelling of 138668436 in words is "one hundred thirty-eight million, six hundred sixty-eight thousand, four hundred thirty-six".