21008943329 has 4 divisors (see below), whose sum is σ = 22918847280. Its totient is φ = 19099039380.

The previous prime is 21008943313. The next prime is 21008943341. The reversal of 21008943329 is 92334980012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21008943329 - 2⁴ = 21008943313 is a prime.

It is a super-2 number, since 2×21008943329² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21008943379) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 954951959 + ... + 954951980.

It is an arithmetic number, because the mean of its divisors is an integer number (5729711820).

Almost surely, 2^21008943329 is an apocalyptic number.

It is an amenable number.

21008943329 is a deficient number, since it is larger than the sum of its proper divisors (1909903951).

21008943329 is a wasteful number, since it uses less digits than its factorization.

21008943329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1909903950.

The product of its (nonzero) digits is 93312, while the sum is 41.

The spelling of 21008943329 in words is "twenty-one billion, eight million, nine hundred forty-three thousand, three hundred twenty-nine".