1668338685520 has 40 divisors (see below), whose sum is σ = 4177263403656. Its totient is φ = 616001975808.

The previous prime is 1668338685509. The next prime is 1668338685523. The reversal of 1668338685520 is 255868338661.

It can be written as a sum of positive squares in 4 ways, for example, as 54686757904 + 1613651927616 = 233852^2 + 1270296^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1668338685523) 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, 802084867 + ... + 802086946.

Almost surely, 2^{1668338685520} is an apocalyptic number.

1668338685520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1668338685520 is an abundant number, since it is smaller than the sum of its proper divisors (2508924718136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1668338685520 is a wasteful number, since it uses less digits than its factorization.

1668338685520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1604171839 (or 1604171833 counting only the distinct ones).

The product of its (nonzero) digits is 49766400, while the sum is 61.

The spelling of 1668338685520 in words is "one trillion, six hundred sixty-eight billion, three hundred thirty-eight million, six hundred eighty-five thousand, five hundred twenty".