211402421 has 2 divisors, whose sum is σ = 211402422. Its totient is φ = 211402420.

The previous prime is 211402409. The next prime is 211402447. The reversal of 211402421 is 124204112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 181306225 + 30096196 = 13465^2 + 5486^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211402421 is a prime.

It is a super-2 number, since 2×211402421² = 89381967209322482, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 211402421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211102421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105701210 + 105701211.

It is an arithmetic number, because the mean of its divisors is an integer number (105701211).

Almost surely, 2^211402421 is an apocalyptic number.

It is an amenable number.

211402421 is a deficient number, since it is larger than the sum of its proper divisors (1).

211402421 is an equidigital number, since it uses as much as digits as its factorization.

211402421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 211402421 is about 14539.6843500813. The cubic root of 211402421 is about 595.7124164344.

Adding to 211402421 its reverse (124204112), we get a palindrome (335606533).

The spelling of 211402421 in words is "two hundred eleven million, four hundred two thousand, four hundred twenty-one".