21585780113 has 2 divisors, whose sum is σ = 21585780114. Its totient is φ = 21585780112.

The previous prime is 21585780101. The next prime is 21585780127. The reversal of 21585780113 is 31108758512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18720533329 + 2865246784 = 136823^2 + 53528^2 .

It is a cyclic number.

It is not a de Polignac number, because 21585780113 - 2²⁶ = 21518671249 is a prime.

It is not a weakly prime, because it can be changed into another prime (21585780173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10792890056 + 10792890057.

It is an arithmetic number, because the mean of its divisors is an integer number (10792890057).

Almost surely, 2^21585780113 is an apocalyptic number.

It is an amenable number.

21585780113 is a deficient number, since it is larger than the sum of its proper divisors (1).

21585780113 is an equidigital number, since it uses as much as digits as its factorization.

21585780113 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 67200, while the sum is 41.

The spelling of 21585780113 in words is "twenty-one billion, five hundred eighty-five million, seven hundred eighty thousand, one hundred thirteen".