218956081 has 2 divisors, whose sum is σ = 218956082. Its totient is φ = 218956080.

The previous prime is 218956051. The next prime is 218956103. The reversal of 218956081 is 180659812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158256400 + 60699681 = 12580^2 + 7791^2 .

It is a cyclic number.

It is not a de Polignac number, because 218956081 - 2²⁵ = 185401649 is a prime.

It is a super-2 number, since 2×218956081² = 95883530813757122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (218956051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109478040 + 109478041.

It is an arithmetic number, because the mean of its divisors is an integer number (109478041).

Almost surely, 2^218956081 is an apocalyptic number.

It is an amenable number.

218956081 is a deficient number, since it is larger than the sum of its proper divisors (1).

218956081 is an equidigital number, since it uses as much as digits as its factorization.

218956081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 40.

The square root of 218956081 is about 14797.1646270493. The cubic root of 218956081 is about 602.7247198101.

The spelling of 218956081 in words is "two hundred eighteen million, nine hundred fifty-six thousand, eighty-one".