218340657 has 16 divisors (see below), whose sum is σ = 333903360. Its totient is φ = 140864400.

The previous prime is 218340641. The next prime is 218340667. The reversal of 218340657 is 756043812.

It is not a de Polignac number, because 218340657 - 2⁴ = 218340641 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (218340667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129594 + ... + 131267.

It is an arithmetic number, because the mean of its divisors is an integer number (20868960).

Almost surely, 2^218340657 is an apocalyptic number.

218340657 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

218340657 is a deficient number, since it is larger than the sum of its proper divisors (115562703).

218340657 is a wasteful number, since it uses less digits than its factorization.

218340657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260901 (or 260895 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 218340657 is about 14776.3546587107. The cubic root of 218340657 is about 602.1594933230.

The spelling of 218340657 in words is "two hundred eighteen million, three hundred forty thousand, six hundred fifty-seven".