21358945669 has 2 divisors, whose sum is σ = 21358945670. Its totient is φ = 21358945668.

The previous prime is 21358945633. The next prime is 21358945687. The reversal of 21358945669 is 96654985312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14577423169 + 6781522500 = 120737^2 + 82350^2 .

It is a cyclic number.

It is not a de Polignac number, because 21358945669 - 2³¹ = 19211462021 is a prime.

It is a super-2 number, since 2×21358945669² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21358945169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10679472834 + 10679472835.

It is an arithmetic number, because the mean of its divisors is an integer number (10679472835).

Almost surely, 2^21358945669 is an apocalyptic number.

It is an amenable number.

21358945669 is a deficient number, since it is larger than the sum of its proper divisors (1).

21358945669 is an equidigital number, since it uses as much as digits as its factorization.

21358945669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13996800, while the sum is 58.

The spelling of 21358945669 in words is "twenty-one billion, three hundred fifty-eight million, nine hundred forty-five thousand, six hundred sixty-nine".