16815544551861 has 8 divisors (see below), whose sum is σ = 24458973893664. Its totient is φ = 10191239122320.

The previous prime is 16815544551797. The next prime is 16815544551881.

16815544551861 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 16815544551861 - 2⁶ = 16815544551797 is a prime.

It is a Smith number, since the sum of its digits (60) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 16815544551795 and 16815544551804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16815544551881) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 254780978026 + ... + 254780978091.

It is an arithmetic number, because the mean of its divisors is an integer number (3057371736708).

Almost surely, 2^{16815544551861} is an apocalyptic number.

16815544551861 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16815544551861 is a deficient number, since it is larger than the sum of its proper divisors (7643429341803).

16815544551861 is a wasteful number, since it uses less digits than its factorization.

16815544551861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509561956131.

The product of its digits is 23040000, while the sum is 60.

The spelling of 16815544551861 in words is "sixteen trillion, eight hundred fifteen billion, five hundred forty-four million, five hundred fifty-one thousand, eight hundred sixty-one".