216021457 has 2 divisors, whose sum is σ = 216021458. Its totient is φ = 216021456.

The previous prime is 216021437. The next prime is 216021461. The reversal of 216021457 is 754120612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 193515921 + 22505536 = 13911^2 + 4744^2 .

It is a cyclic number.

It is not a de Polignac number, because 216021457 - 2¹⁹ = 215497169 is a prime.

It is a Chen prime.

It is equal to p_11915533 and since 216021457 and 11915533 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (216021427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108010728 + 108010729.

It is an arithmetic number, because the mean of its divisors is an integer number (108010729).

Almost surely, 2^216021457 is an apocalyptic number.

It is an amenable number.

216021457 is a deficient number, since it is larger than the sum of its proper divisors (1).

216021457 is an equidigital number, since it uses as much as digits as its factorization.

216021457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 216021457 is about 14697.6684205353. The cubic root of 216021457 is about 600.0198669348.

The spelling of 216021457 in words is "two hundred sixteen million, twenty-one thousand, four hundred fifty-seven".