138808784 has 20 divisors (see below), whose sum is σ = 269996484. Its totient is φ = 69132288.

The previous prime is 138808783. The next prime is 138808801. The reversal of 138808784 is 487808831.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 118810000 + 19998784 = 10900^2 + 4472^2 .

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138808783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12767 + ... + 20990.

Almost surely, 2^138808784 is an apocalyptic number.

It is an amenable number.

138808784 is a deficient number, since it is larger than the sum of its proper divisors (131187700).

138808784 is a wasteful number, since it uses less digits than its factorization.

138808784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34022 (or 34016 counting only the distinct ones).

The product of its (nonzero) digits is 344064, while the sum is 47.

The square root of 138808784 is about 11781.7139669914. The cubic root of 138808784 is about 517.7725033727.

Adding to 138808784 its sum of digits (47), we get a palindrome (138808831).

It can be divided in two parts, 13880 and 8784, that multiplied together give a triangular number (121921920 = T₁₅₆₁₅).

The spelling of 138808784 in words is "one hundred thirty-eight million, eight hundred eight thousand, seven hundred eighty-four".