216138539 has 2 divisors, whose sum is σ = 216138540. Its totient is φ = 216138538.

The previous prime is 216138529. The next prime is 216138569. The reversal of 216138539 is 935831612.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 216138539 - 2⁴ = 216138523 is a prime.

It is not a weakly prime, because it can be changed into another prime (216138529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108069269 + 108069270.

It is an arithmetic number, because the mean of its divisors is an integer number (108069270).

Almost surely, 2^216138539 is an apocalyptic number.

216138539 is a deficient number, since it is larger than the sum of its proper divisors (1).

216138539 is an equidigital number, since it uses as much as digits as its factorization.

216138539 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 38.

The square root of 216138539 is about 14701.6508936922. The cubic root of 216138539 is about 600.1282494367.

The spelling of 216138539 in words is "two hundred sixteen million, one hundred thirty-eight thousand, five hundred thirty-nine".