18717888211645 has 24 divisors (see below), whose sum is σ = 26834823531864. Its totient is φ = 12488228113536.

The previous prime is 18717888211637. The next prime is 18717888211657. The reversal of 18717888211645 is 54611288871781.

It can be written as a sum of positive squares in 4 ways, for example, as 2419857136921 + 16298031074724 = 1555589^2 + 4037082^2 .

It is not a de Polignac number, because 18717888211645 - 2³ = 18717888211637 is a prime.

It is a Smith number, since the sum of its digits (67) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

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, 1032417202 + ... + 1032435331.

It is an arithmetic number, because the mean of its divisors is an integer number (1118117647161).

Almost surely, 2^{18717888211645} is an apocalyptic number.

It is an amenable number.

18717888211645 is a deficient number, since it is larger than the sum of its proper divisors (8116935320219).

18717888211645 is a wasteful number, since it uses less digits than its factorization.

18717888211645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2064852589 (or 2064852582 counting only the distinct ones).

The product of its digits is 48168960, while the sum is 67.

The spelling of 18717888211645 in words is "eighteen trillion, seven hundred seventeen billion, eight hundred eighty-eight million, two hundred eleven thousand, six hundred forty-five".