216657720767 has 4 divisors (see below), whose sum is σ = 217019420400. Its totient is φ = 216296021136.

The previous prime is 216657720743. The next prime is 216657720779. The reversal of 216657720767 is 767027756612.

It is a happy number.

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 216657720767 - 2⁸ = 216657720511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216657720967) 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, 180848918 + ... + 180850115.

It is an arithmetic number, because the mean of its divisors is an integer number (54254855100).

Almost surely, 2^216657720767 is an apocalyptic number.

216657720767 is a deficient number, since it is larger than the sum of its proper divisors (361699633).

216657720767 is an equidigital number, since it uses as much as digits as its factorization.

216657720767 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361699632.

The product of its (nonzero) digits is 10372320, while the sum is 56.

The spelling of 216657720767 in words is "two hundred sixteen billion, six hundred fifty-seven million, seven hundred twenty thousand, seven hundred sixty-seven".