21333309997 has 2 divisors, whose sum is σ = 21333309998. Its totient is φ = 21333309996.

The previous prime is 21333309947. The next prime is 21333310001. The reversal of 21333309997 is 79990333312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14561007561 + 6772302436 = 120669^2 + 82294^2 .

It is a cyclic number.

It is not a de Polignac number, because 21333309997 - 2⁷ = 21333309869 is a prime.

It is a super-2 number, since 2×21333309997² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21333309997.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21333309947) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10666654998 + 10666654999.

It is an arithmetic number, because the mean of its divisors is an integer number (10666654999).

Almost surely, 2^21333309997 is an apocalyptic number.

It is an amenable number.

21333309997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21333309997 is an equidigital number, since it uses as much as digits as its factorization.

21333309997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 826686, while the sum is 49.

The spelling of 21333309997 in words is "twenty-one billion, three hundred thirty-three million, three hundred nine thousand, nine hundred ninety-seven".