21172580755 has 4 divisors (see below), whose sum is σ = 25407096912. Its totient is φ = 16938064600.

The previous prime is 21172580711. The next prime is 21172580771. The reversal of 21172580755 is 55708527112.

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

It is not a de Polignac number, because 21172580755 - 2¹⁵ = 21172547987 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2117258071 + ... + 2117258080.

It is an arithmetic number, because the mean of its divisors is an integer number (6351774228).

Almost surely, 2^21172580755 is an apocalyptic number.

21172580755 is a deficient number, since it is larger than the sum of its proper divisors (4234516157).

21172580755 is an equidigital number, since it uses as much as digits as its factorization.

21172580755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4234516156.

The product of its (nonzero) digits is 196000, while the sum is 43.

The spelling of 21172580755 in words is "twenty-one billion, one hundred seventy-two million, five hundred eighty thousand, seven hundred fifty-five".