218484440981 has 4 divisors (see below), whose sum is σ = 219261965964. Its totient is φ = 217706916000.

The previous prime is 218484440971. The next prime is 218484441013. The reversal of 218484440981 is 189044484812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 84312413956 + 134172027025 = 290366^2 + 366295^2 .

It is a cyclic number.

It is not a de Polignac number, because 218484440981 - 2¹⁸ = 218484178837 is a prime.

It is a super-2 number, since 2×218484440981² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218484440971) 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, 388762070 + ... + 388762631.

It is an arithmetic number, because the mean of its divisors is an integer number (54815491491).

Almost surely, 2^218484440981 is an apocalyptic number.

It is an amenable number.

218484440981 is a deficient number, since it is larger than the sum of its proper divisors (777524983).

218484440981 is an equidigital number, since it uses as much as digits as its factorization.

218484440981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 777524982.

The product of its (nonzero) digits is 2359296, while the sum is 53.

The spelling of 218484440981 in words is "two hundred eighteen billion, four hundred eighty-four million, four hundred forty thousand, nine hundred eighty-one".