21436063421 has 2 divisors, whose sum is σ = 21436063422. Its totient is φ = 21436063420.

The previous prime is 21436063409. The next prime is 21436063471. The reversal of 21436063421 is 12436063412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11111268100 + 10324795321 = 105410^2 + 101611^2 .

It is a cyclic number.

It is not a de Polignac number, because 21436063421 - 2⁶ = 21436063357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21436063471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10718031710 + 10718031711.

It is an arithmetic number, because the mean of its divisors is an integer number (10718031711).

Almost surely, 2^21436063421 is an apocalyptic number.

It is an amenable number.

21436063421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21436063421 is an equidigital number, since it uses as much as digits as its factorization.

21436063421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 32.

Subtracting from 21436063421 its reverse (12436063412), we obtain a palindrome (9000000009).

The spelling of 21436063421 in words is "twenty-one billion, four hundred thirty-six million, sixty-three thousand, four hundred twenty-one".