21604145146553 has 2 divisors, whose sum is σ = 21604145146554. Its totient is φ = 21604145146552.

The previous prime is 21604145146523. The next prime is 21604145146561. The reversal of 21604145146553 is 35564154140612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21419152254889 + 184992891664 = 4628083^2 + 430108^2 .

It is a cyclic number.

It is not a de Polignac number, because 21604145146553 - 2¹⁰ = 21604145145529 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21604145146498 and 21604145146507.

It is not a weakly prime, because it can be changed into another prime (21604145146523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802072573276 + 10802072573277.

It is an arithmetic number, because the mean of its divisors is an integer number (10802072573277).

Almost surely, 2^{21604145146553} is an apocalyptic number.

It is an amenable number.

21604145146553 is a deficient number, since it is larger than the sum of its proper divisors (1).

21604145146553 is an equidigital number, since it uses as much as digits as its factorization.

21604145146553 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728000, while the sum is 47.

The spelling of 21604145146553 in words is "twenty-one trillion, six hundred four billion, one hundred forty-five million, one hundred forty-six thousand, five hundred fifty-three".