211505531 has 2 divisors, whose sum is σ = 211505532. Its totient is φ = 211505530.

The previous prime is 211505513. The next prime is 211505537. The reversal of 211505531 is 135505112.

It is a happy number.

Together with previous prime (211505513) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211505531 is a prime.

It is a super-2 number, since 2×211505531² = 89469179287183922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 211505497 and 211505506.

It is not a weakly prime, because it can be changed into another prime (211505537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105752765 + 105752766.

It is an arithmetic number, because the mean of its divisors is an integer number (105752766).

Almost surely, 2^211505531 is an apocalyptic number.

211505531 is a deficient number, since it is larger than the sum of its proper divisors (1).

211505531 is an equidigital number, since it uses as much as digits as its factorization.

211505531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 750, while the sum is 23.

The square root of 211505531 is about 14543.2297307029. The cubic root of 211505531 is about 595.8092521649.

The spelling of 211505531 in words is "two hundred eleven million, five hundred five thousand, five hundred thirty-one".