128695596821 has 4 divisors (see below), whose sum is σ = 140395196544. Its totient is φ = 116995997100.

The previous prime is 128695596781. The next prime is 128695596853.

128695596821 is nontrivially palindromic in base 10.

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 128695596821 - 2¹⁰ = 128695595797 is a prime.

It is a super-2 number, since 2×128695596821² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128695596881) 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, 5849799845 + ... + 5849799866.

It is an arithmetic number, because the mean of its divisors is an integer number (35098799136).

Almost surely, 2^128695596821 is an apocalyptic number.

128695596821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128695596821 is a deficient number, since it is larger than the sum of its proper divisors (11699599723).

128695596821 is a wasteful number, since it uses less digits than its factorization.

128695596821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11699599722.

The product of its digits is 18662400, while the sum is 62.

The spelling of 128695596821 in words is "one hundred twenty-eight billion, six hundred ninety-five million, five hundred ninety-six thousand, eight hundred twenty-one".