216990777 has 4 divisors (see below), whose sum is σ = 289321040. Its totient is φ = 144660516.

The previous prime is 216990751. The next prime is 216990817. The reversal of 216990777 is 777099612.

216990777 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 216990777 - 2⁶ = 216990713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216990727) 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, 36165127 + ... + 36165132.

It is an arithmetic number, because the mean of its divisors is an integer number (72330260).

Almost surely, 2^216990777 is an apocalyptic number.

It is an amenable number.

216990777 is a deficient number, since it is larger than the sum of its proper divisors (72330263).

216990777 is an equidigital number, since it uses as much as digits as its factorization.

216990777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72330262.

The product of its (nonzero) digits is 333396, while the sum is 48.

The square root of 216990777 is about 14730.6068103117. The cubic root of 216990777 is about 600.9159870125.

The spelling of 216990777 in words is "two hundred sixteen million, nine hundred ninety thousand, seven hundred seventy-seven".