211471309 has 6 divisors (see below), whose sum is σ = 245997294. Its totient is φ = 181261080.

The previous prime is 211471261. The next prime is 211471321. The reversal of 211471309 is 903174112.

It can be written as a sum of positive squares in only one way, i.e., 122168809 + 89302500 = 11053^2 + 9450^2 .

It is not a de Polignac number, because 211471309 - 2¹⁵ = 211438541 is a prime.

It is a super-2 number, since 2×211471309² = 89440229060346962, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211471339) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2157822 + ... + 2157919.

It is an arithmetic number, because the mean of its divisors is an integer number (40999549).

Almost surely, 2^211471309 is an apocalyptic number.

It is an amenable number.

211471309 is a deficient number, since it is larger than the sum of its proper divisors (34525985).

211471309 is an equidigital number, since it uses as much as digits as its factorization.

211471309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4315755 (or 4315748 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 211471309 is about 14542.0531218944. The cubic root of 211471309 is about 595.7771160722. Note that the first 3 decimals are identical.

The spelling of 211471309 in words is "two hundred eleven million, four hundred seventy-one thousand, three hundred nine".