216258778 has 4 divisors (see below), whose sum is σ = 324388170. Its totient is φ = 108129388.

The previous prime is 216258773. The next prime is 216258803. The reversal of 216258778 is 877852612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 187881849 + 28376929 = 13707^2 + 5327^2 .

It is not an unprimeable number, because it can be changed into a prime (216258773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54064693 + ... + 54064696.

Almost surely, 2^216258778 is an apocalyptic number.

216258778 is a deficient number, since it is larger than the sum of its proper divisors (108129392).

216258778 is a wasteful number, since it uses less digits than its factorization.

216258778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108129391.

The product of its digits is 376320, while the sum is 46.

The square root of 216258778 is about 14705.7396277780. The cubic root of 216258778 is about 600.2395136352.

It can be divided in two parts, 21625 and 8778, that added together give a palindrome (30403).

The spelling of 216258778 in words is "two hundred sixteen million, two hundred fifty-eight thousand, seven hundred seventy-eight".