216643426 has 8 divisors (see below), whose sum is σ = 332891244. Its totient is φ = 105679680.

The previous prime is 216643423. The next prime is 216643447. The reversal of 216643426 is 624346612.

It can be written as a sum of positive squares in 2 ways, for example, as 208831401 + 7812025 = 14451^2 + 2795^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 216643391 and 216643400.

It is not an unprimeable number, because it can be changed into a prime (216643423) 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, 1320915 + ... + 1321078.

Almost surely, 2^216643426 is an apocalyptic number.

216643426 is a deficient number, since it is larger than the sum of its proper divisors (116247818).

216643426 is a wasteful number, since it uses less digits than its factorization.

216643426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2642036.

The product of its digits is 41472, while the sum is 34.

The square root of 216643426 is about 14718.8119765150. The cubic root of 216643426 is about 600.5951742323.

The spelling of 216643426 in words is "two hundred sixteen million, six hundred forty-three thousand, four hundred twenty-six".