21643435545 has 8 divisors (see below), whose sum is σ = 34629496896. Its totient is φ = 11543165616.

The previous prime is 21643435543. The next prime is 21643435579. The reversal of 21643435545 is 54553434612.

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

It is not a de Polignac number, because 21643435545 - 2¹ = 21643435543 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21643435497 and 21643435506.

It is not an unprimeable number, because it can be changed into a prime (21643435543) 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, 721447837 + ... + 721447866.

It is an arithmetic number, because the mean of its divisors is an integer number (4328687112).

Almost surely, 2^21643435545 is an apocalyptic number.

It is an amenable number.

21643435545 is a deficient number, since it is larger than the sum of its proper divisors (12986061351).

21643435545 is a wasteful number, since it uses less digits than its factorization.

21643435545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1442895711.

The product of its digits is 864000, while the sum is 42.

The spelling of 21643435545 in words is "twenty-one billion, six hundred forty-three million, four hundred thirty-five thousand, five hundred forty-five".