21152335155409 has 2 divisors, whose sum is σ = 21152335155410. Its totient is φ = 21152335155408.

The previous prime is 21152335155389. The next prime is 21152335155433. The reversal of 21152335155409 is 90455153325112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21100903719184 + 51431436225 = 4593572^2 + 226785^2 .

It is a cyclic number.

It is not a de Polignac number, because 21152335155409 - 2²⁹ = 21151798284497 is a prime.

It is not a weakly prime, because it can be changed into another prime (21152335155109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10576167577704 + 10576167577705.

It is an arithmetic number, because the mean of its divisors is an integer number (10576167577705).

Almost surely, 2^{21152335155409} is an apocalyptic number.

It is an amenable number.

21152335155409 is a deficient number, since it is larger than the sum of its proper divisors (1).

21152335155409 is an equidigital number, since it uses as much as digits as its factorization.

21152335155409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 810000, while the sum is 46.

The spelling of 21152335155409 in words is "twenty-one trillion, one hundred fifty-two billion, three hundred thirty-five million, one hundred fifty-five thousand, four hundred nine".