21307765047 has 16 divisors (see below), whose sum is σ = 28678193280. Its totient is φ = 14071322592.

The previous prime is 21307765043. The next prime is 21307765049. The reversal of 21307765047 is 74056770312.

It is not a de Polignac number, because 21307765047 - 2² = 21307765043 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21307765043) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2246008 + ... + 2255474.

It is an arithmetic number, because the mean of its divisors is an integer number (1792387080).

Almost surely, 2^21307765047 is an apocalyptic number.

21307765047 is a deficient number, since it is larger than the sum of its proper divisors (7370428233).

21307765047 is a wasteful number, since it uses less digits than its factorization.

21307765047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16462.

The product of its (nonzero) digits is 246960, while the sum is 42.

The spelling of 21307765047 in words is "twenty-one billion, three hundred seven million, seven hundred sixty-five thousand, forty-seven".