128220111221591 has 24 divisors (see below), whose sum is σ = 142134090387840. Its totient is φ = 115426064327552.

The previous prime is 128220111221563. The next prime is 128220111221603. The reversal of 128220111221591 is 195122111022821.

It is a de Polignac number, because none of the positive numbers 2^k-128220111221591 is a prime.

It is a super-3 number, since 3×128220111221591³ (a number of 43 digits) contains 333 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 (128220111223591) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 163517240 + ... + 164299506.

It is an arithmetic number, because the mean of its divisors is an integer number (5922253766160).

Almost surely, 2^{128220111221591} is an apocalyptic number.

128220111221591 is a deficient number, since it is larger than the sum of its proper divisors (13913979166249).

128220111221591 is a wasteful number, since it uses less digits than its factorization.

128220111221591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 806983 (or 806966 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 38.

The spelling of 128220111221591 in words is "one hundred twenty-eight trillion, two hundred twenty billion, one hundred eleven million, two hundred twenty-one thousand, five hundred ninety-one".