218477961 has 27 divisors (see below), whose sum is σ = 342625959. Its totient is φ = 134093232.

The previous prime is 218477939. The next prime is 218477983. The reversal of 218477961 is 169774812.

It is a happy number.

The square root of 218477961 is 14781.

It is a perfect power (a square), and thus also a powerful number.

It is an interprime number because it is at equal distance from previous prime (218477939) and next prime (218477983).

It can be written as a sum of positive squares in only one way, i.e., 32319225 + 186158736 = 5685^2 + 13644^2 .

It is not a de Polignac number, because 218477961 - 2⁹ = 218477449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (218477911) 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 26 ways as a sum of consecutive naturals, for example, 576270 + ... + 576648.

Almost surely, 2^218477961 is an apocalyptic number.

218477961 is the 14781-st square number.

218477961 is the 7391-st centered octagonal number.

It is an amenable number.

218477961 is a deficient number, since it is larger than the sum of its proper divisors (124147998).

218477961 is an equidigital number, since it uses as much as digits as its factorization.

218477961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 790 (or 395 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The cubic root of 218477961 is about 602.2856899788.

The spelling of 218477961 in words is "two hundred eighteen million, four hundred seventy-seven thousand, nine hundred sixty-one".