1688722353521 has 4 divisors (see below), whose sum is σ = 1929968404032. Its totient is φ = 1447476303012.

The previous prime is 1688722353491. The next prime is 1688722353523. The reversal of 1688722353521 is 1253532278861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1688722353521 - 2²² = 1688718159217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1688722353523) 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, 120623025245 + ... + 120623025258.

It is an arithmetic number, because the mean of its divisors is an integer number (482492101008).

Almost surely, 2^{1688722353521} is an apocalyptic number.

It is an amenable number.

1688722353521 is a deficient number, since it is larger than the sum of its proper divisors (241246050511).

1688722353521 is an equidigital number, since it uses as much as digits as its factorization.

1688722353521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241246050510.

The product of its digits is 4838400, while the sum is 53.

The spelling of 1688722353521 in words is "one trillion, six hundred eighty-eight billion, seven hundred twenty-two million, three hundred fifty-three thousand, five hundred twenty-one".