16505780331 has 16 divisors (see below), whose sum is σ = 22857327360. Its totient is φ = 10582068000.

The previous prime is 16505780311. The next prime is 16505780353. The reversal of 16505780331 is 13308750561.

It is a happy number.

It is not a de Polignac number, because 16505780331 - 2⁵ = 16505780299 is a prime.

It is a super-2 number, since 2×16505780331² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 16505780331.

It is not an unprimeable number, because it can be changed into a prime (16505780311) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 356095 + ... + 399768.

It is an arithmetic number, because the mean of its divisors is an integer number (1428582960).

Almost surely, 2^16505780331 is an apocalyptic number.

16505780331 is a deficient number, since it is larger than the sum of its proper divisors (6351547029).

16505780331 is a wasteful number, since it uses less digits than its factorization.

16505780331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 756146.

The product of its (nonzero) digits is 75600, while the sum is 39.

The spelling of 16505780331 in words is "sixteen billion, five hundred five million, seven hundred eighty thousand, three hundred thirty-one".