216651445 has 4 divisors (see below), whose sum is σ = 259981740. Its totient is φ = 173321152.

The previous prime is 216651427. The next prime is 216651469. The reversal of 216651445 is 544156612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 89548369 + 127103076 = 9463^2 + 11274^2 .

It is a cyclic number.

It is not a de Polignac number, because 216651445 - 2¹⁷ = 216520373 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216651445.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 21665140 + ... + 21665149.

It is an arithmetic number, because the mean of its divisors is an integer number (64995435).

Almost surely, 2^216651445 is an apocalyptic number.

It is an amenable number.

216651445 is a deficient number, since it is larger than the sum of its proper divisors (43330295).

216651445 is an equidigital number, since it uses as much as digits as its factorization.

216651445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43330294.

The product of its digits is 28800, while the sum is 34.

The square root of 216651445 is about 14719.0843804905. The cubic root of 216651445 is about 600.6025844322.

The spelling of 216651445 in words is "two hundred sixteen million, six hundred fifty-one thousand, four hundred forty-five".