216786257 has 4 divisors (see below), whose sum is σ = 228196080. Its totient is φ = 205376436.

The previous prime is 216786239. The next prime is 216786259. The reversal of 216786257 is 752687612.

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 a cyclic number.

It is not a de Polignac number, because 216786257 - 2²⁴ = 200009041 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216786259) 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, 5704883 + ... + 5704920.

It is an arithmetic number, because the mean of its divisors is an integer number (57049020).

Almost surely, 2^216786257 is an apocalyptic number.

It is an amenable number.

216786257 is a deficient number, since it is larger than the sum of its proper divisors (11409823).

216786257 is a wasteful number, since it uses less digits than its factorization.

216786257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11409822.

The product of its digits is 282240, while the sum is 44.

The square root of 216786257 is about 14723.6631651230. The cubic root of 216786257 is about 600.7271341779.

The spelling of 216786257 in words is "two hundred sixteen million, seven hundred eighty-six thousand, two hundred fifty-seven".