214821721 has 2 divisors, whose sum is σ = 214821722. Its totient is φ = 214821720.

The previous prime is 214821713. The next prime is 214821751. The reversal of 214821721 is 127128412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 206324496 + 8497225 = 14364^2 + 2915^2 .

It is a cyclic number.

It is not a de Polignac number, because 214821721 - 2³ = 214821713 is a prime.

It is a super-2 number, since 2×214821721² = 92296743626803682, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 214821721.

It is not a weakly prime, because it can be changed into another prime (214821751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107410860 + 107410861.

It is an arithmetic number, because the mean of its divisors is an integer number (107410861).

Almost surely, 2^214821721 is an apocalyptic number.

It is an amenable number.

214821721 is a deficient number, since it is larger than the sum of its proper divisors (1).

214821721 is an equidigital number, since it uses as much as digits as its factorization.

214821721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1792, while the sum is 28.

The square root of 214821721 is about 14656.7977744117. The cubic root of 214821721 is about 598.9070110937.

The spelling of 214821721 in words is "two hundred fourteen million, eight hundred twenty-one thousand, seven hundred twenty-one".