21768708307 has 4 divisors (see below), whose sum is σ = 22470924736. Its totient is φ = 21066491880.

The previous prime is 21768708287. The next prime is 21768708319. The reversal of 21768708307 is 70380786712.

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 21768708307 - 2¹⁹ = 21768184019 is a prime.

It is a super-2 number, since 2×21768708307² (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 (21768708347) 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, 351108168 + ... + 351108229.

It is an arithmetic number, because the mean of its divisors is an integer number (5617731184).

Almost surely, 2^21768708307 is an apocalyptic number.

21768708307 is a deficient number, since it is larger than the sum of its proper divisors (702216429).

21768708307 is an equidigital number, since it uses as much as digits as its factorization.

21768708307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 702216428.

The product of its (nonzero) digits is 790272, while the sum is 49.

The spelling of 21768708307 in words is "twenty-one billion, seven hundred sixty-eight million, seven hundred eight thousand, three hundred seven".