218407820 has 24 divisors (see below), whose sum is σ = 469844928. Its totient is φ = 85232000.

The previous prime is 218407817. The next prime is 218407841. The reversal of 218407820 is 28704812.

It is an unprimeable number.

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, 132356 + ... + 133995.

It is an arithmetic number, because the mean of its divisors is an integer number (19576872).

Almost surely, 2^218407820 is an apocalyptic number.

218407820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

218407820 is an abundant number, since it is smaller than the sum of its proper divisors (251437108).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

218407820 is a wasteful number, since it uses less digits than its factorization.

218407820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 266401 (or 266399 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 218407820 is about 14778.6271351570. The cubic root of 218407820 is about 602.2212297131.

The spelling of 218407820 in words is "two hundred eighteen million, four hundred seven thousand, eight hundred twenty".