16218744781261 has 4 divisors (see below), whose sum is σ = 17693176125024. Its totient is φ = 14744313437500.

The previous prime is 16218744781249. The next prime is 16218744781279.

16218744781261 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16218744781261 - 2⁴³ = 7422651759053 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 16218744781196 and 16218744781205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16218744788261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 737215671865 + ... + 737215671886.

It is an arithmetic number, because the mean of its divisors is an integer number (4423294031256).

Almost surely, 2^{16218744781261} is an apocalyptic number.

16218744781261 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16218744781261 is a deficient number, since it is larger than the sum of its proper divisors (1474431343763).

16218744781261 is a wasteful number, since it uses less digits than its factorization.

16218744781261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1474431343762.

The product of its digits is 7225344, while the sum is 58.

The spelling of 16218744781261 in words is "sixteen trillion, two hundred eighteen billion, seven hundred forty-four million, seven hundred eighty-one thousand, two hundred sixty-one".