21033021091 has 2 divisors, whose sum is σ = 21033021092. Its totient is φ = 21033021090.

The previous prime is 21033021083. The next prime is 21033021127. The reversal of 21033021091 is 19012033012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21033021091 - 2³ = 21033021083 is a prime.

It is a super-4 number, since 4×21033021091⁴ (a number of 42 digits) contains 4444 as substring.

It is not a weakly prime, because it can be changed into another prime (21033021011) 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, 10516510545 + 10516510546.

It is an arithmetic number, because the mean of its divisors is an integer number (10516510546).

Almost surely, 2^21033021091 is an apocalyptic number.

21033021091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21033021091 is an equidigital number, since it uses as much as digits as its factorization.

21033021091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 22.

The spelling of 21033021091 in words is "twenty-one billion, thirty-three million, twenty-one thousand, ninety-one".