128021691353 has 4 divisors (see below), whose sum is σ = 128022627300. Its totient is φ = 128020755408.

The previous prime is 128021691341. The next prime is 128021691397. The reversal of 128021691353 is 353196120821.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 19367732224 + 108653959129 = 139168^2 + 329627^2 .

It is a cyclic number.

It is not a de Polignac number, because 128021691353 - 2¹⁸ = 128021429209 is a prime.

It is a super-3 number, since 3×128021691353³ (a number of 34 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128021691353.

It is not an unprimeable number, because it can be changed into a prime (128021691313) 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, 218450 + ... + 551147.

It is an arithmetic number, because the mean of its divisors is an integer number (32005656825).

Almost surely, 2^128021691353 is an apocalyptic number.

It is an amenable number.

128021691353 is a deficient number, since it is larger than the sum of its proper divisors (935947).

128021691353 is an equidigital number, since it uses as much as digits as its factorization.

128021691353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 935946.

The product of its (nonzero) digits is 77760, while the sum is 41.

The spelling of 128021691353 in words is "one hundred twenty-eight billion, twenty-one million, six hundred ninety-one thousand, three hundred fifty-three".