215455811 has 2 divisors, whose sum is σ = 215455812. Its totient is φ = 215455810.

The previous prime is 215455781. The next prime is 215455813. The reversal of 215455811 is 118554512.

215455811 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-215455811 is a prime.

It is a Sophie Germain prime.

Together with 215455813, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (215455813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107727905 + 107727906.

It is an arithmetic number, because the mean of its divisors is an integer number (107727906).

Almost surely, 2^215455811 is an apocalyptic number.

215455811 is a deficient number, since it is larger than the sum of its proper divisors (1).

215455811 is an equidigital number, since it uses as much as digits as its factorization.

215455811 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8000, while the sum is 32.

The square root of 215455811 is about 14678.4130954269. The cubic root of 215455811 is about 599.4956975468.

The spelling of 215455811 in words is "two hundred fifteen million, four hundred fifty-five thousand, eight hundred eleven".