1917721378896 has 40 divisors (see below), whose sum is σ = 4954170755040. Its totient is φ = 639233079936.

The previous prime is 1917721378891. The next prime is 1917721378939. The reversal of 1917721378896 is 6988731277191.

It is a self number, because there is not a number n which added to its sum of digits gives 1917721378896.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1917721378891) 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, 5375451 + ... + 5721093.

It is an arithmetic number, because the mean of its divisors is an integer number (123854268876).

Almost surely, 2^{1917721378896} is an apocalyptic number.

1917721378896 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1917721378896 is an abundant number, since it is smaller than the sum of its proper divisors (3036449376144).

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

1917721378896 is a wasteful number, since it uses less digits than its factorization.

1917721378896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461243 (or 461237 counting only the distinct ones).

The product of its digits is 64012032, while the sum is 69.

The spelling of 1917721378896 in words is "one trillion, nine hundred seventeen billion, seven hundred twenty-one million, three hundred seventy-eight thousand, eight hundred ninety-six".