21696856473601 has 4 divisors (see below), whose sum is σ = 21725070852100. Its totient is φ = 21668642095104.

The previous prime is 21696856473559. The next prime is 21696856473671. The reversal of 21696856473601 is 10637465869612.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13289495266576 + 8407361207025 = 3645476^2 + 2899545^2 .

It is a cyclic number.

It is not a de Polignac number, because 21696856473601 - 2¹³ = 21696856465409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21696856473671) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14107188096 + ... + 14107189633.

It is an arithmetic number, because the mean of its divisors is an integer number (5431267713025).

It is a 1-persistent number, because it is pandigital, but 2⋅21696856473601 = 43393712947202 is not.

Almost surely, 2^{21696856473601} is an apocalyptic number.

It is an amenable number.

21696856473601 is a deficient number, since it is larger than the sum of its proper divisors (28214378499).

21696856473601 is an equidigital number, since it uses as much as digits as its factorization.

21696856473601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28214378498.

The product of its (nonzero) digits is 78382080, while the sum is 64.

The spelling of 21696856473601 in words is "twenty-one trillion, six hundred ninety-six billion, eight hundred fifty-six million, four hundred seventy-three thousand, six hundred one".