21279016907 has 4 divisors (see below), whose sum is σ = 21296055000. Its totient is φ = 21261978816.

The previous prime is 21279016901. The next prime is 21279016981. The reversal of 21279016907 is 70961097212.

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 21279016907 - 2²² = 21274822603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21279016901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8517173 + ... + 8519670.

It is an arithmetic number, because the mean of its divisors is an integer number (5324013750).

Almost surely, 2^21279016907 is an apocalyptic number.

21279016907 is a deficient number, since it is larger than the sum of its proper divisors (17038093).

21279016907 is a wasteful number, since it uses less digits than its factorization.

21279016907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17038092.

The product of its (nonzero) digits is 95256, while the sum is 44.

The spelling of 21279016907 in words is "twenty-one billion, two hundred seventy-nine million, sixteen thousand, nine hundred seven".