21545335807 has 4 divisors (see below), whose sum is σ = 21545676880. Its totient is φ = 21544994736.

The previous prime is 21545335787. The next prime is 21545335879. The reversal of 21545335807 is 70853354512.

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 21545335807 - 2¹¹ = 21545333759 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21545335607) 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, 44958 + ... + 212395.

It is an arithmetic number, because the mean of its divisors is an integer number (5386419220).

Almost surely, 2^21545335807 is an apocalyptic number.

21545335807 is a deficient number, since it is larger than the sum of its proper divisors (341073).

21545335807 is an equidigital number, since it uses as much as digits as its factorization.

21545335807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 341072.

The product of its (nonzero) digits is 504000, while the sum is 43.

The spelling of 21545335807 in words is "twenty-one billion, five hundred forty-five million, three hundred thirty-five thousand, eight hundred seven".