216856947 has 8 divisors (see below), whose sum is σ = 306151056. Its totient is φ = 136067072.

The previous prime is 216856943. The next prime is 216856961. The reversal of 216856947 is 749658612.

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

It is a cyclic number.

It is not a de Polignac number, because 216856947 - 2² = 216856943 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 216856896 and 216856905.

It is not an unprimeable number, because it can be changed into a prime (216856943) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2125998 + ... + 2126099.

It is an arithmetic number, because the mean of its divisors is an integer number (38268882).

Almost surely, 2^216856947 is an apocalyptic number.

216856947 is a deficient number, since it is larger than the sum of its proper divisors (89294109).

216856947 is a wasteful number, since it uses less digits than its factorization.

216856947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4252117.

The product of its digits is 725760, while the sum is 48.

The square root of 216856947 is about 14726.0635269579. The cubic root of 216856947 is about 600.7924224282.

The spelling of 216856947 in words is "two hundred sixteen million, eight hundred fifty-six thousand, nine hundred forty-seven".