211421989 has 2 divisors, whose sum is σ = 211421990. Its totient is φ = 211421988.

The previous prime is 211421981. The next prime is 211421993. The reversal of 211421989 is 989124112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207849889 + 3572100 = 14417^2 + 1890^2 .

It is a cyclic number.

It is not a de Polignac number, because 211421989 - 2³ = 211421981 is a prime.

It is a super-2 number, since 2×211421989² = 89398514865432242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211421981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105710994 + 105710995.

It is an arithmetic number, because the mean of its divisors is an integer number (105710995).

Almost surely, 2^211421989 is an apocalyptic number.

It is an amenable number.

211421989 is a deficient number, since it is larger than the sum of its proper divisors (1).

211421989 is an equidigital number, since it uses as much as digits as its factorization.

211421989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 37.

The square root of 211421989 is about 14540.3572514571. The cubic root of 211421989 is about 595.7307961371.

The spelling of 211421989 in words is "two hundred eleven million, four hundred twenty-one thousand, nine hundred eighty-nine".