138121215 has 8 divisors (see below), whose sum is σ = 220993968. Its totient is φ = 73664640.

The previous prime is 138121201. The next prime is 138121223. The reversal of 138121215 is 512121831.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 138121215 - 2¹⁷ = 137990143 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4604026 + ... + 4604055.

It is an arithmetic number, because the mean of its divisors is an integer number (27624246).

Almost surely, 2^138121215 is an apocalyptic number.

138121215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

138121215 is a deficient number, since it is larger than the sum of its proper divisors (82872753).

138121215 is an equidigital number, since it uses as much as digits as its factorization.

138121215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9208089.

The product of its digits is 480, while the sum is 24.

The square root of 138121215 is about 11752.4982450541. The cubic root of 138121215 is about 516.9161844854.

The spelling of 138121215 in words is "one hundred thirty-eight million, one hundred twenty-one thousand, two hundred fifteen".