16355823778881 has 6 divisors (see below), whose sum is σ = 23625078791730. Its totient is φ = 10903882519248.

The previous prime is 16355823778867. The next prime is 16355823779011. The reversal of 16355823778881 is 18887732855361.

It is a happy number.

16355823778881 is a `hidden beast` number, since 1 + 6 + 3 + 5 + 582 + 37 + 7 + 8 + 8 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 15110012865600 + 1245810913281 = 3887160^2 + 1116159^2 .

It is not a de Polignac number, because 16355823778881 - 2³⁰ = 16354750037057 is a prime.

It is a super-2 number, since 2×16355823778881² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (16355823778781) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 908656876596 + ... + 908656876613.

It is an arithmetic number, because the mean of its divisors is an integer number (3937513131955).

Almost surely, 2^{16355823778881} is an apocalyptic number.

It is an amenable number.

16355823778881 is a deficient number, since it is larger than the sum of its proper divisors (7269255012849).

16355823778881 is a wasteful number, since it uses less digits than its factorization.

16355823778881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1817313753215 (or 1817313753212 counting only the distinct ones).

The product of its digits is 541900800, while the sum is 72.

The spelling of 16355823778881 in words is "sixteen trillion, three hundred fifty-five billion, eight hundred twenty-three million, seven hundred seventy-eight thousand, eight hundred eighty-one".