216649057 has 2 divisors, whose sum is σ = 216649058. Its totient is φ = 216649056.

The previous prime is 216649031. The next prime is 216649087. The reversal of 216649057 is 750946612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 203946961 + 12702096 = 14281^2 + 3564^2 .

It is a cyclic number.

It is not a de Polignac number, because 216649057 - 2¹⁵ = 216616289 is a prime.

It is equal to p_11948179 and since 216649057 and 11948179 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 (216649087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108324528 + 108324529.

It is an arithmetic number, because the mean of its divisors is an integer number (108324529).

Almost surely, 2^216649057 is an apocalyptic number.

It is an amenable number.

216649057 is a deficient number, since it is larger than the sum of its proper divisors (1).

216649057 is an equidigital number, since it uses as much as digits as its factorization.

216649057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 90720, while the sum is 40.

The square root of 216649057 is about 14719.0032610907. The cubic root of 216649057 is about 600.6003777476.

The spelling of 216649057 in words is "two hundred sixteen million, six hundred forty-nine thousand, fifty-seven".