218676421 has 2 divisors, whose sum is σ = 218676422. Its totient is φ = 218676420.

The previous prime is 218676397. The next prime is 218676461. The reversal of 218676421 is 124676812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 218625796 + 50625 = 14786^2 + 225^2 .

It is a cyclic number.

It is not a de Polignac number, because 218676421 - 2²³ = 210287813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (218676461) 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 as a sum of consecutive naturals, namely, 109338210 + 109338211.

It is an arithmetic number, because the mean of its divisors is an integer number (109338211).

Almost surely, 2^218676421 is an apocalyptic number.

It is an amenable number.

218676421 is a deficient number, since it is larger than the sum of its proper divisors (1).

218676421 is an equidigital number, since it uses as much as digits as its factorization.

218676421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 37.

The square root of 218676421 is about 14787.7118243493. The cubic root of 218676421 is about 602.4680019507.

The spelling of 218676421 in words is "two hundred eighteen million, six hundred seventy-six thousand, four hundred twenty-one".