1668395778280 has 128 divisors (see below), whose sum is σ = 4926500352000. Its totient is φ = 492650000640.

The previous prime is 1668395778277. The next prime is 1668395778293. The reversal of 1668395778280 is 828775938661.

It is a hoax number, since the sum of its digits (70) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (70).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14196400 + ... + 14313439.

It is an arithmetic number, because the mean of its divisors is an integer number (38488284000).

Almost surely, 2^{1668395778280} is an apocalyptic number.

1668395778280 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1668395778280 is an abundant number, since it is smaller than the sum of its proper divisors (3258104573720).

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

1668395778280 is a wasteful number, since it uses less digits than its factorization.

1668395778280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28509887 (or 28509883 counting only the distinct ones).

The product of its (nonzero) digits is 243855360, while the sum is 70.

The spelling of 1668395778280 in words is "one trillion, six hundred sixty-eight billion, three hundred ninety-five million, seven hundred seventy-eight thousand, two hundred eighty".