21033109997 has 2 divisors, whose sum is σ = 21033109998. Its totient is φ = 21033109996.

The previous prime is 21033109963. The next prime is 21033110011. The reversal of 21033109997 is 79990133012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15662272201 + 5370837796 = 125149^2 + 73286^2 .

It is a cyclic number.

It is not a de Polignac number, because 21033109997 - 2¹⁰ = 21033108973 is a prime.

It is a super-2 number, since 2×21033109997² (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 (21033105997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10516554998 + 10516554999.

It is an arithmetic number, because the mean of its divisors is an integer number (10516554999).

Almost surely, 2^21033109997 is an apocalyptic number.

It is an amenable number.

21033109997 is a deficient number, since it is larger than the sum of its proper divisors (1).

21033109997 is an equidigital number, since it uses as much as digits as its factorization.

21033109997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 91854, while the sum is 44.

The spelling of 21033109997 in words is "twenty-one billion, thirty-three million, one hundred nine thousand, nine hundred ninety-seven".