128421199873 has 16 divisors (see below), whose sum is σ = 133851801600. Its totient is φ = 123060409920.

The previous prime is 128421199847. The next prime is 128421199889. The reversal of 128421199873 is 378991124821.

It is a cyclic number.

It is not a de Polignac number, because 128421199873 - 2¹⁷ = 128421068801 is a prime.

It is a super-2 number, since 2×128421199873² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128421199073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2405215 + ... + 2458027.

It is an arithmetic number, because the mean of its divisors is an integer number (8365737600).

It is a Proth number, since it is equal to 15309 ⋅ 2²³ + 1 and 15309 < 2²³.

Almost surely, 2^128421199873 is an apocalyptic number.

It is an amenable number.

128421199873 is a deficient number, since it is larger than the sum of its proper divisors (5430601727).

128421199873 is a wasteful number, since it uses less digits than its factorization.

128421199873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53472.

The product of its digits is 1741824, while the sum is 55.

The spelling of 128421199873 in words is "one hundred twenty-eight billion, four hundred twenty-one million, one hundred ninety-nine thousand, eight hundred seventy-three".