218961081 has 24 divisors (see below), whose sum is σ = 332666880. Its totient is φ = 138511296.

The previous prime is 218961059. The next prime is 218961103. The reversal of 218961081 is 180169812.

It is an interprime number because it is at equal distance from previous prime (218961059) and next prime (218961103).

It is not a de Polignac number, because 218961081 - 2⁷ = 218960953 is a prime.

It is a super-2 number, since 2×218961081² = 95887909985377122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (218961181) 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 23 ways as a sum of consecutive naturals, for example, 22125 + ... + 30453.

It is an arithmetic number, because the mean of its divisors is an integer number (13861120).

Almost surely, 2^218961081 is an apocalyptic number.

It is an amenable number.

218961081 is a deficient number, since it is larger than the sum of its proper divisors (113705799).

218961081 is a wasteful number, since it uses less digits than its factorization.

218961081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8485 (or 8482 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 36.

The square root of 218961081 is about 14797.3335773713. Note that the first 3 decimals coincide. The cubic root of 218961081 is about 602.7293076414.

The spelling of 218961081 in words is "two hundred eighteen million, nine hundred sixty-one thousand, eighty-one".