216138904 has 16 divisors (see below), whose sum is σ = 416214000. Its totient is φ = 105148512.

The previous prime is 216138893. The next prime is 216138907. The reversal of 216138904 is 409831612.

It is a self number, because there is not a number n which added to its sum of digits gives 216138904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216138907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 364804 + ... + 365395.

It is an arithmetic number, because the mean of its divisors is an integer number (26013375).

Almost surely, 2^216138904 is an apocalyptic number.

It is an amenable number.

216138904 is a deficient number, since it is larger than the sum of its proper divisors (200075096).

216138904 is a wasteful number, since it uses less digits than its factorization.

216138904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 730242 (or 730238 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 216138904 is about 14701.6633072588. The cubic root of 216138904 is about 600.1285872550.

The spelling of 216138904 in words is "two hundred sixteen million, one hundred thirty-eight thousand, nine hundred four".