216161778 has 32 divisors (see below), whose sum is σ = 494631936. Its totient is φ = 61692048.

The previous prime is 216161713. The next prime is 216161801. The reversal of 216161778 is 877161612.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44875 + ... + 49457.

It is an arithmetic number, because the mean of its divisors is an integer number (15457248).

Almost surely, 2^216161778 is an apocalyptic number.

216161778 is an abundant number, since it is smaller than the sum of its proper divisors (278470158).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216161778 is a wasteful number, since it uses less digits than its factorization.

216161778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5718.

The product of its digits is 28224, while the sum is 39.

The square root of 216161778 is about 14702.4412258645. The cubic root of 216161778 is about 600.1497570627.

The spelling of 216161778 in words is "two hundred sixteen million, one hundred sixty-one thousand, seven hundred seventy-eight".