138520971 has 6 divisors (see below), whose sum is σ = 200085860. Its totient is φ = 92347308.

The previous prime is 138520969. The next prime is 138521003. The reversal of 138520971 is 179025831.

138520971 is a `hidden beast` number, since 1 + 385 + 209 + 71 = 666.

It is not a de Polignac number, because 138520971 - 2¹ = 138520969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138520901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7695601 + ... + 7695618.

Almost surely, 2^138520971 is an apocalyptic number.

138520971 is a deficient number, since it is larger than the sum of its proper divisors (61564889).

138520971 is a wasteful number, since it uses less digits than its factorization.

138520971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15391225 (or 15391222 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 36.

The square root of 138520971 is about 11769.4932346299. The cubic root of 138520971 is about 517.4143973790.

It can be divided in two parts, 1385209 and 71, that added together give a triangular number (1385280 = T₁₆₆₄).

The spelling of 138520971 in words is "one hundred thirty-eight million, five hundred twenty thousand, nine hundred seventy-one".