21765534347 has 16 divisors (see below), whose sum is σ = 22237501440. Its totient is φ = 21299252832.

The previous prime is 21765534319. The next prime is 21765534353. The reversal of 21765534347 is 74343556712.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21765534347 - 2¹⁰ = 21765533323 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21765534377) 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, 4918778 + ... + 4923200.

It is an arithmetic number, because the mean of its divisors is an integer number (1389843840).

Almost surely, 2^21765534347 is an apocalyptic number.

21765534347 is a deficient number, since it is larger than the sum of its proper divisors (471967093).

21765534347 is a wasteful number, since it uses less digits than its factorization.

21765534347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5042.

The product of its digits is 2116800, while the sum is 47.

The spelling of 21765534347 in words is "twenty-one billion, seven hundred sixty-five million, five hundred thirty-four thousand, three hundred forty-seven".