21508583755 has 8 divisors (see below), whose sum is σ = 26297287632. Its totient is φ = 16882208928.

The previous prime is 21508583749. The next prime is 21508583777. The reversal of 21508583755 is 55738580512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21508583755 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21508583699 and 21508583708.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40581969 + ... + 40582498.

It is an arithmetic number, because the mean of its divisors is an integer number (3287160954).

Almost surely, 2^21508583755 is an apocalyptic number.

21508583755 is a deficient number, since it is larger than the sum of its proper divisors (4788703877).

21508583755 is an equidigital number, since it uses as much as digits as its factorization.

21508583755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81164525.

The product of its (nonzero) digits is 1680000, while the sum is 49.

The spelling of 21508583755 in words is "twenty-one billion, five hundred eight million, five hundred eighty-three thousand, seven hundred fifty-five".