18173408049781 has 8 divisors (see below), whose sum is σ = 18221672362424. Its totient is φ = 18125156237760.

The previous prime is 18173408049779. The next prime is 18173408049851. The reversal of 18173408049781 is 18794080437181.

It can be written as a sum of positive squares in 4 ways, for example, as 708038102500 + 17465369947281 = 841450^2 + 4179159^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 18173408049781 - 2¹ = 18173408049779 is a prime.

It is a super-2 number, since 2×18173408049781² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18173400049781) 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, 210090 + ... + 6032491.

It is an arithmetic number, because the mean of its divisors is an integer number (2277709045303).

Almost surely, 2^{18173408049781} is an apocalyptic number.

It is an amenable number.

18173408049781 is a deficient number, since it is larger than the sum of its proper divisors (48264312643).

18173408049781 is an equidigital number, since it uses as much as digits as its factorization.

18173408049781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6250311.

The product of its (nonzero) digits is 10838016, while the sum is 61.

The spelling of 18173408049781 in words is "eighteen trillion, one hundred seventy-three billion, four hundred eight million, forty-nine thousand, seven hundred eighty-one".