21906643906153 has 2 divisors, whose sum is σ = 21906643906154. Its totient is φ = 21906643906152.

The previous prime is 21906643905997. The next prime is 21906643906253. The reversal of 21906643906153 is 35160934660912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15346939445289 + 6559704460864 = 3917517^2 + 2561192^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21906643906153 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21906643906094 and 21906643906103.

It is not a weakly prime, because it can be changed into another prime (21906643906253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10953321953076 + 10953321953077.

It is an arithmetic number, because the mean of its divisors is an integer number (10953321953077).

Almost surely, 2^{21906643906153} is an apocalyptic number.

It is an amenable number.

21906643906153 is a deficient number, since it is larger than the sum of its proper divisors (1).

21906643906153 is an equidigital number, since it uses as much as digits as its factorization.

21906643906153 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6298560, while the sum is 55.

The spelling of 21906643906153 in words is "twenty-one trillion, nine hundred six billion, six hundred forty-three million, nine hundred six thousand, one hundred fifty-three".