218370921 has 8 divisors (see below), whose sum is σ = 291280704. Its totient is φ = 145520880.

The previous prime is 218370907. The next prime is 218370949. The reversal of 218370921 is 129073812.

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

It is not a de Polignac number, because 218370921 - 2⁷ = 218370793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (218370421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5565 + ... + 21626.

It is an arithmetic number, because the mean of its divisors is an integer number (36410088).

Almost surely, 2^218370921 is an apocalyptic number.

It is an amenable number.

218370921 is a deficient number, since it is larger than the sum of its proper divisors (72909783).

218370921 is a wasteful number, since it uses less digits than its factorization.

218370921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29871.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 218370921 is about 14777.3786917707. The cubic root of 218370921 is about 602.1873136310.

The spelling of 218370921 in words is "two hundred eighteen million, three hundred seventy thousand, nine hundred twenty-one".