21217783067 has 4 divisors (see below), whose sum is σ = 22849920240. Its totient is φ = 19585645896.

The previous prime is 21217783063. The next prime is 21217783087. The reversal of 21217783067 is 76038771212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21217783067 - 2² = 21217783063 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21217783063) 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 in 3 ways as a sum of consecutive naturals, for example, 816068567 + ... + 816068592.

It is an arithmetic number, because the mean of its divisors is an integer number (5712480060).

Almost surely, 2^21217783067 is an apocalyptic number.

21217783067 is a deficient number, since it is larger than the sum of its proper divisors (1632137173).

21217783067 is a wasteful number, since it uses less digits than its factorization.

21217783067 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632137172.

The product of its (nonzero) digits is 197568, while the sum is 44.

The spelling of 21217783067 in words is "twenty-one billion, two hundred seventeen million, seven hundred eighty-three thousand, sixty-seven".