21203453669 has 2 divisors, whose sum is σ = 21203453670. Its totient is φ = 21203453668.

The previous prime is 21203453659. The next prime is 21203453671. The reversal of 21203453669 is 96635430212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21202272100 + 1181569 = 145610^2 + 1087^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203453669 - 2¹² = 21203449573 is a prime.

It is a super-2 number, since 2×21203453669² (a number of 21 digits) contains 22 as substring.

Together with 21203453671, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21203453659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601726834 + 10601726835.

It is an arithmetic number, because the mean of its divisors is an integer number (10601726835).

Almost surely, 2^21203453669 is an apocalyptic number.

It is an amenable number.

21203453669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203453669 is an equidigital number, since it uses as much as digits as its factorization.

21203453669 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 41.

The spelling of 21203453669 in words is "twenty-one billion, two hundred three million, four hundred fifty-three thousand, six hundred sixty-nine".