21128041591 has 12 divisors (see below), whose sum is σ = 22332967272. Its totient is φ = 19985163984.

The previous prime is 21128041559. The next prime is 21128041633. The reversal of 21128041591 is 19514082112.

It is not a de Polignac number, because 21128041591 - 2⁵ = 21128041559 is a prime.

It is a super-2 number, since 2×21128041591² (a number of 21 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 (21128041391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 190920 + ... + 280546.

It is an arithmetic number, because the mean of its divisors is an integer number (1861080606).

Almost surely, 2^21128041591 is an apocalyptic number.

21128041591 is a deficient number, since it is larger than the sum of its proper divisors (1204925681).

21128041591 is an equidigital number, since it uses as much as digits as its factorization.

21128041591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90318 (or 90299 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 34.

The spelling of 21128041591 in words is "twenty-one billion, one hundred twenty-eight million, forty-one thousand, five hundred ninety-one".