216462721 has 2 divisors, whose sum is σ = 216462722. Its totient is φ = 216462720.

The previous prime is 216462643. The next prime is 216462749. The reversal of 216462721 is 127264612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 206784400 + 9678321 = 14380^2 + 3111^2 .

It is a cyclic number.

It is not a de Polignac number, because 216462721 - 2¹⁷ = 216331649 is a prime.

It is a super-2 number, since 2×216462721² = 93712219165447682, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216462761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108231360 + 108231361.

It is an arithmetic number, because the mean of its divisors is an integer number (108231361).

Almost surely, 2^216462721 is an apocalyptic number.

It is an amenable number.

216462721 is a deficient number, since it is larger than the sum of its proper divisors (1).

216462721 is an equidigital number, since it uses as much as digits as its factorization.

216462721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8064, while the sum is 31.

The square root of 216462721 is about 14712.6721230373. The cubic root of 216462721 is about 600.4281397916.

The spelling of 216462721 in words is "two hundred sixteen million, four hundred sixty-two thousand, seven hundred twenty-one".