211404421 has 4 divisors (see below), whose sum is σ = 217118092. Its totient is φ = 205690752.

The previous prime is 211404409. The next prime is 211404433. The reversal of 211404421 is 124404112.

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

It is an interprime number because it is at equal distance from previous prime (211404409) and next prime (211404433).

It can be written as a sum of positive squares in 2 ways, for example, as 196280100 + 15124321 = 14010^2 + 3889^2 .

It is a cyclic number.

It is not a de Polignac number, because 211404421 - 2¹⁵ = 211371653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211404451) 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 3 ways as a sum of consecutive naturals, for example, 2856780 + ... + 2856853.

It is an arithmetic number, because the mean of its divisors is an integer number (54279523).

Almost surely, 2^211404421 is an apocalyptic number.

It is an amenable number.

211404421 is a deficient number, since it is larger than the sum of its proper divisors (5713671).

211404421 is an equidigital number, since it uses as much as digits as its factorization.

211404421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5713670.

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 211404421 is about 14539.7531272027. The cubic root of 211404421 is about 595.7142950333.

Adding to 211404421 its reverse (124404112), we get a palindrome (335808533).

The spelling of 211404421 in words is "two hundred eleven million, four hundred four thousand, four hundred twenty-one".