216656651 has 4 divisors (see below), whose sum is σ = 224127600. Its totient is φ = 209185704.

The previous prime is 216656647. The next prime is 216656717. The reversal of 216656651 is 156656612.

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

It is a cyclic number.

It is not a de Polignac number, because 216656651 - 2² = 216656647 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216656621) 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, 3735431 + ... + 3735488.

It is an arithmetic number, because the mean of its divisors is an integer number (56031900).

Almost surely, 2^216656651 is an apocalyptic number.

216656651 is a deficient number, since it is larger than the sum of its proper divisors (7470949).

216656651 is an equidigital number, since it uses as much as digits as its factorization.

216656651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7470948.

The product of its digits is 64800, while the sum is 38.

The square root of 216656651 is about 14719.2612246675. The cubic root of 216656651 is about 600.6073950964.

The spelling of 216656651 in words is "two hundred sixteen million, six hundred fifty-six thousand, six hundred fifty-one".