1668518520377 has 4 divisors (see below), whose sum is σ = 1668652993140. Its totient is φ = 1668384047616.

The previous prime is 1668518520367. The next prime is 1668518520407. The reversal of 1668518520377 is 7730258158661.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 602728638736 + 1065789881641 = 776356^2 + 1032371^2 .

It is a cyclic number.

It is not a de Polignac number, because 1668518520377 - 2¹² = 1668518516281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1668518520367) 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, 67217768 + ... + 67242585.

It is an arithmetic number, because the mean of its divisors is an integer number (417163248285).

Almost surely, 2^{1668518520377} is an apocalyptic number.

It is an amenable number.

1668518520377 is a deficient number, since it is larger than the sum of its proper divisors (134472763).

1668518520377 is a wasteful number, since it uses less digits than its factorization.

1668518520377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134472762.

The product of its (nonzero) digits is 16934400, while the sum is 59.

The spelling of 1668518520377 in words is "one trillion, six hundred sixty-eight billion, five hundred eighteen million, five hundred twenty thousand, three hundred seventy-seven".