216457 has 4 divisors (see below), whose sum is σ = 217620. Its totient is φ = 215296.

The previous prime is 216451. The next prime is 216481. The reversal of 216457 is 754612.

216457 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 19321 + 197136 = 139^2 + 444^2 .

It is a 3-Lehmer number, since φ(216457) divides (216457-1)³.

It is a cyclic number.

It is not a de Polignac number, because 216457 - 2⁷ = 216329 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (216451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 232 + ... + 697.

It is an arithmetic number, because the mean of its divisors is an integer number (54405).

2²¹⁶⁴⁵⁷ is an apocalyptic number.

216457 is the 233-rd decagonal number.

It is an amenable number.

216457 is a deficient number, since it is larger than the sum of its proper divisors (1163).

216457 is an equidigital number, since it uses as much as digits as its factorization.

216457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1162.

The product of its digits is 1680, while the sum is 25.

The square root of 216457 is about 465.2493954859. The cubic root of 216457 is about 60.0422850074.

The spelling of 216457 in words is "two hundred sixteen thousand, four hundred fifty-seven".