21066721107 has 8 divisors (see below), whose sum is σ = 28090292160. Its totient is φ = 14043815400.

The previous prime is 21066721099. The next prime is 21066721127. The reversal of 21066721107 is 70112766012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21066721107 - 2³ = 21066721099 is a prime.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21066721127) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87057 + ... + 222962.

It is an arithmetic number, because the mean of its divisors is an integer number (3511286520).

Almost surely, 2^21066721107 is an apocalyptic number.

21066721107 is a deficient number, since it is larger than the sum of its proper divisors (7023571053).

21066721107 is a wasteful number, since it uses less digits than its factorization.

21066721107 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332673.

The product of its (nonzero) digits is 7056, while the sum is 33.

The spelling of 21066721107 in words is "twenty-one billion, sixty-six million, seven hundred twenty-one thousand, one hundred seven".