21235693168513 has 2 divisors, whose sum is σ = 21235693168514. Its totient is φ = 21235693168512.

The previous prime is 21235693168499. The next prime is 21235693168523. The reversal of 21235693168513 is 31586139653212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15374805629184 + 5860887539329 = 3921072^2 + 2420927^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21235693168513 is a prime.

It is not a weakly prime, because it can be changed into another prime (21235693168523) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10617846584256 + 10617846584257.

It is an arithmetic number, because the mean of its divisors is an integer number (10617846584257).

Almost surely, 2^{21235693168513} is an apocalyptic number.

It is an amenable number.

21235693168513 is a deficient number, since it is larger than the sum of its proper divisors (1).

21235693168513 is an equidigital number, since it uses as much as digits as its factorization.

21235693168513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6998400, while the sum is 55.

The spelling of 21235693168513 in words is "twenty-one trillion, two hundred thirty-five billion, six hundred ninety-three million, one hundred sixty-eight thousand, five hundred thirteen".