218138857 has 8 divisors (see below), whose sum is σ = 221052384. Its totient is φ = 215232288.

The previous prime is 218138839. The next prime is 218138861. The reversal of 218138857 is 758831812.

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

It is a cyclic number.

It is not a de Polignac number, because 218138857 - 2⁷ = 218138729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (218138827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97918 + ... + 100120.

It is an arithmetic number, because the mean of its divisors is an integer number (27631548).

Almost surely, 2^218138857 is an apocalyptic number.

It is an amenable number.

218138857 is a deficient number, since it is larger than the sum of its proper divisors (2913527).

218138857 is a wasteful number, since it uses less digits than its factorization.

218138857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3479.

The product of its digits is 107520, while the sum is 43.

The square root of 218138857 is about 14769.5246030466. The cubic root of 218138857 is about 601.9739220794.

The spelling of 218138857 in words is "two hundred eighteen million, one hundred thirty-eight thousand, eight hundred fifty-seven".