21505530075766 has 16 divisors (see below), whose sum is σ = 35191691211600. Its totient is φ = 9775012106080.

The previous prime is 21505530075763. The next prime is 21505530075769. The reversal of 21505530075766 is 66757003550512.

It is an interprime number because it is at equal distance from previous prime (21505530075763) and next prime (21505530075769).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21505530075761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10478941 + ... + 12362008.

It is an arithmetic number, because the mean of its divisors is an integer number (2199480700725).

Almost surely, 2^{21505530075766} is an apocalyptic number.

21505530075766 is a deficient number, since it is larger than the sum of its proper divisors (13686161135834).

21505530075766 is a wasteful number, since it uses less digits than its factorization.

21505530075766 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22883759.

The product of its (nonzero) digits is 6615000, while the sum is 52.

The spelling of 21505530075766 in words is "twenty-one trillion, five hundred five billion, five hundred thirty million, seventy-five thousand, seven hundred sixty-six".