21111573755 has 4 divisors (see below), whose sum is σ = 25333888512. Its totient is φ = 16889259000.

The previous prime is 21111573751. The next prime is 21111573757. The reversal of 21111573755 is 55737511112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21111573755 - 2² = 21111573751 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111573751) 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 3 ways as a sum of consecutive naturals, for example, 2111157371 + ... + 2111157380.

It is an arithmetic number, because the mean of its divisors is an integer number (6333472128).

Almost surely, 2^21111573755 is an apocalyptic number.

21111573755 is a deficient number, since it is larger than the sum of its proper divisors (4222314757).

21111573755 is an equidigital number, since it uses as much as digits as its factorization.

21111573755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4222314756.

The product of its digits is 36750, while the sum is 38.

The spelling of 21111573755 in words is "twenty-one billion, one hundred eleven million, five hundred seventy-three thousand, seven hundred fifty-five".