216138938 has 4 divisors (see below), whose sum is σ = 324208410. Its totient is φ = 108069468.

The previous prime is 216138919. The next prime is 216138961. The reversal of 216138938 is 839831612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 159693769 + 56445169 = 12637^2 + 7513^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 216138895 and 216138904.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54034733 + ... + 54034736.

Almost surely, 2^216138938 is an apocalyptic number.

216138938 is a deficient number, since it is larger than the sum of its proper divisors (108069472).

216138938 is a wasteful number, since it uses less digits than its factorization.

216138938 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108069471.

The product of its digits is 62208, while the sum is 41.

The square root of 216138938 is about 14701.6644635905. The cubic root of 216138938 is about 600.1286187230.

The spelling of 216138938 in words is "two hundred sixteen million, one hundred thirty-eight thousand, nine hundred thirty-eight".