138439287 has 32 divisors (see below), whose sum is σ = 237314560. Its totient is φ = 79099416.

The previous prime is 138439267. The next prime is 138439291. The reversal of 138439287 is 782934831.

138439287 is a `hidden beast` number, since 138 + 439 + 2 + 87 = 666.

It is not a de Polignac number, because 138439287 - 2⁸ = 138439031 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138439207) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10788 + ... + 19830.

It is an arithmetic number, because the mean of its divisors is an integer number (7416080).

Almost surely, 2^138439287 is an apocalyptic number.

138439287 is a deficient number, since it is larger than the sum of its proper divisors (98875273).

138439287 is an frugal number, since it uses more digits than its factorization.

138439287 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9071 (or 9053 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 138439287 is about 11766.0225649962. The cubic root of 138439287 is about 517.3126732197.

The spelling of 138439287 in words is "one hundred thirty-eight million, four hundred thirty-nine thousand, two hundred eighty-seven".