16661121112215 has 24 divisors (see below), whose sum is σ = 29583649197648. Its totient is φ = 8669201228160.

The previous prime is 16661121112193. The next prime is 16661121112241. The reversal of 16661121112215 is 51221112116661.

16661121112215 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 16661121112215 - 2¹⁴ = 16661121095831 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16661121112215.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4515207129 + ... + 4515210818.

It is an arithmetic number, because the mean of its divisors is an integer number (1232652049902).

Almost surely, 2^{16661121112215} is an apocalyptic number.

16661121112215 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

16661121112215 is a deficient number, since it is larger than the sum of its proper divisors (12922528085433).

16661121112215 is a wasteful number, since it uses less digits than its factorization.

16661121112215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9030417999 (or 9030417996 counting only the distinct ones).

The product of its digits is 8640, while the sum is 36.

Adding to 16661121112215 its reverse (51221112116661), we get a palindrome (67882233228876).

The spelling of 16661121112215 in words is "sixteen trillion, six hundred sixty-one billion, one hundred twenty-one million, one hundred twelve thousand, two hundred fifteen".