138156215 has 4 divisors (see below), whose sum is σ = 165787464. Its totient is φ = 110524968.

The previous prime is 138156199. The next prime is 138156217. The reversal of 138156215 is 512651831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 512651831 = 191 ⋅2684041.

It is a cyclic number.

It is not a de Polignac number, because 138156215 - 2⁴ = 138156199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138156217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13815617 + ... + 13815626.

It is an arithmetic number, because the mean of its divisors is an integer number (41446866).

Almost surely, 2^138156215 is an apocalyptic number.

138156215 is a deficient number, since it is larger than the sum of its proper divisors (27631249).

138156215 is an equidigital number, since it uses as much as digits as its factorization.

138156215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27631248.

The product of its digits is 7200, while the sum is 32.

The square root of 138156215 is about 11753.9871958412. The cubic root of 138156215 is about 516.9598430899.

The spelling of 138156215 in words is "one hundred thirty-eight million, one hundred fifty-six thousand, two hundred fifteen".