211421521 has 2 divisors, whose sum is σ = 211421522. Its totient is φ = 211421520.

The previous prime is 211421489. The next prime is 211421549. The reversal of 211421521 is 125124112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 173290896 + 38130625 = 13164^2 + 6175^2 .

It is a cyclic number.

It is not a de Polignac number, because 211421521 - 2⁵ = 211421489 is a prime.

It is not a weakly prime, because it can be changed into another prime (211421591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105710760 + 105710761.

It is an arithmetic number, because the mean of its divisors is an integer number (105710761).

Almost surely, 2^211421521 is an apocalyptic number.

It is an amenable number.

211421521 is a deficient number, since it is larger than the sum of its proper divisors (1).

211421521 is an equidigital number, since it uses as much as digits as its factorization.

211421521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 160, while the sum is 19.

The square root of 211421521 is about 14540.3411583085. The cubic root of 211421521 is about 595.7303565703.

Adding to 211421521 its reverse (125124112), we get a palindrome (336545633).

The spelling of 211421521 in words is "two hundred eleven million, four hundred twenty-one thousand, five hundred twenty-one".