21645122611 has 8 divisors (see below), whose sum is σ = 24894846560. Its totient is φ = 18434789568.

The previous prime is 21645122599. The next prime is 21645122621. The reversal of 21645122611 is 11622154612.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21645122611 - 2⁹ = 21645122099 is a prime.

It is a super-2 number, since 2×21645122611² (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 (21645122621) 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, 9846546 + ... + 9848743.

It is an arithmetic number, because the mean of its divisors is an integer number (3111855820).

Almost surely, 2^21645122611 is an apocalyptic number.

21645122611 is a deficient number, since it is larger than the sum of its proper divisors (3249723949).

21645122611 is a wasteful number, since it uses less digits than its factorization.

21645122611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19695453.

The product of its digits is 5760, while the sum is 31.

The spelling of 21645122611 in words is "twenty-one billion, six hundred forty-five million, one hundred twenty-two thousand, six hundred eleven".