216743251 has 4 divisors (see below), whose sum is σ = 229492872. Its totient is φ = 203993632.

The previous prime is 216743231. The next prime is 216743257. The reversal of 216743251 is 152347612.

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 216743251 - 2¹³ = 216735059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216743257) by changing a digit.

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, 6374785 + ... + 6374818.

It is an arithmetic number, because the mean of its divisors is an integer number (57373218).

Almost surely, 2^216743251 is an apocalyptic number.

216743251 is a deficient number, since it is larger than the sum of its proper divisors (12749621).

216743251 is a wasteful number, since it uses less digits than its factorization.

216743251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12749620.

The product of its digits is 10080, while the sum is 31.

The square root of 216743251 is about 14722.2026544943. The cubic root of 216743251 is about 600.6874075211.

The spelling of 216743251 in words is "two hundred sixteen million, seven hundred forty-three thousand, two hundred fifty-one".