1993721721721 has 8 divisors (see below), whose sum is σ = 2008889375360. Its totient is φ = 1978565844528.

The previous prime is 1993721721713. The next prime is 1993721721749. The reversal of 1993721721721 is 1271271273991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1993721721721 - 2³ = 1993721721713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1993421721721) 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, 2604081 + ... + 3281566.

It is an arithmetic number, because the mean of its divisors is an integer number (251111171920).

Almost surely, 2^{1993721721721} is an apocalyptic number.

It is an amenable number.

1993721721721 is a deficient number, since it is larger than the sum of its proper divisors (15167653639).

1993721721721 is a wasteful number, since it uses less digits than its factorization.

1993721721721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5888223.

The product of its digits is 666792, while the sum is 52.

The spelling of 1993721721721 in words is "one trillion, nine hundred ninety-three billion, seven hundred twenty-one million, seven hundred twenty-one thousand, seven hundred twenty-one".