215066021 has 2 divisors, whose sum is σ = 215066022. Its totient is φ = 215066020.

The previous prime is 215066017. The next prime is 215066023. The reversal of 215066021 is 120660512.

215066021 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 can be written as a sum of positive squares in only one way, i.e., 109202500 + 105863521 = 10450^2 + 10289^2 .

It is a cyclic number.

It is not a de Polignac number, because 215066021 - 2² = 215066017 is a prime.

Together with 215066023, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215066023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107533010 + 107533011.

It is an arithmetic number, because the mean of its divisors is an integer number (107533011).

Almost surely, 2^215066021 is an apocalyptic number.

It is an amenable number.

215066021 is a deficient number, since it is larger than the sum of its proper divisors (1).

215066021 is an equidigital number, since it uses as much as digits as its factorization.

215066021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 215066021 is about 14665.1294232271. The cubic root of 215066021 is about 599.1339551750.

The spelling of 215066021 in words is "two hundred fifteen million, sixty-six thousand, twenty-one".