218394649 has 4 divisors (see below), whose sum is σ = 238248720. Its totient is φ = 198540580.

The previous prime is 218394641. The next prime is 218394703. The reversal of 218394649 is 946493812.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 218394649 - 2³ = 218394641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 218394599 and 218394608.

It is not an unprimeable number, because it can be changed into a prime (218394641) 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, 9927019 + ... + 9927040.

It is an arithmetic number, because the mean of its divisors is an integer number (59562180).

Almost surely, 2^218394649 is an apocalyptic number.

It is an amenable number.

218394649 is a deficient number, since it is larger than the sum of its proper divisors (19854071).

218394649 is a wasteful number, since it uses less digits than its factorization.

218394649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19854070.

The product of its digits is 373248, while the sum is 46.

The square root of 218394649 is about 14778.1815187120. The cubic root of 218394649 is about 602.2091238962.

The spelling of 218394649 in words is "two hundred eighteen million, three hundred ninety-four thousand, six hundred forty-nine".