216656553 has 4 divisors (see below), whose sum is σ = 288875408. Its totient is φ = 144437700.

The previous prime is 216656549. The next prime is 216656569. The reversal of 216656553 is 355656612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 216656553 - 2² = 216656549 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216656513) 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, 36109423 + ... + 36109428.

It is an arithmetic number, because the mean of its divisors is an integer number (72218852).

Almost surely, 2^216656553 is an apocalyptic number.

It is an amenable number.

216656553 is a deficient number, since it is larger than the sum of its proper divisors (72218855).

216656553 is an equidigital number, since it uses as much as digits as its factorization.

216656553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72218854.

The product of its digits is 162000, while the sum is 39.

The square root of 216656553 is about 14719.2578956957. The cubic root of 216656553 is about 600.6073045390.

The spelling of 216656553 in words is "two hundred sixteen million, six hundred fifty-six thousand, five hundred fifty-three".