21506065057744 has 20 divisors (see below), whose sum is σ = 42238795586596. Its totient is φ = 10605730712832.

The previous prime is 21506065057723. The next prime is 21506065057753. The reversal of 21506065057744 is 44775056060512.

It can be written as a sum of positive squares in 2 ways, for example, as 6553149447744 + 14952915610000 = 2559912^2 + 3866900^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21506065057691 and 21506065057700.

It is a congruent 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, 9206362299 + ... + 9206364634.

Almost surely, 2^{21506065057744} is an apocalyptic number.

It is an amenable number.

21506065057744 is a deficient number, since it is larger than the sum of its proper divisors (20732730528852).

21506065057744 is a wasteful number, since it uses less digits than its factorization.

21506065057744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18412727014 (or 18412727008 counting only the distinct ones).

The product of its (nonzero) digits is 7056000, while the sum is 52.

The spelling of 21506065057744 in words is "twenty-one trillion, five hundred six billion, sixty-five million, fifty-seven thousand, seven hundred forty-four".