211420021 has 4 divisors (see below), whose sum is σ = 215409132. Its totient is φ = 207430912.

The previous prime is 211420009. The next prime is 211420043. The reversal of 211420021 is 120024112.

It is a happy number.

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 191268900 + 20151121 = 13830^2 + 4489^2 .

It is a cyclic number.

It is not a de Polignac number, because 211420021 - 2⁷ = 211419893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 211419983 and 211420010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211420051) 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, 1994476 + ... + 1994581.

It is an arithmetic number, because the mean of its divisors is an integer number (53852283).

Almost surely, 2^211420021 is an apocalyptic number.

It is an amenable number.

211420021 is a deficient number, since it is larger than the sum of its proper divisors (3989111).

211420021 is an equidigital number, since it uses as much as digits as its factorization.

211420021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3989110.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 211420021 is about 14540.2895775841. The cubic root of 211420021 is about 595.7289476982.

Adding to 211420021 its reverse (120024112), we get a palindrome (331444133).

The spelling of 211420021 in words is "two hundred eleven million, four hundred twenty thousand, twenty-one".