21489877909 has 8 divisors (see below), whose sum is σ = 21791893760. Its totient is φ = 21188612016.

The previous prime is 21489877889. The next prime is 21489877919. The reversal of 21489877909 is 90977898412.

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 21489877909 - 2²¹ = 21487780757 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 (21489877919) 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, 129654 + ... + 244519.

It is an arithmetic number, because the mean of its divisors is an integer number (2723986720).

Almost surely, 2^21489877909 is an apocalyptic number.

It is an amenable number.

21489877909 is a deficient number, since it is larger than the sum of its proper divisors (302015851).

21489877909 is an equidigital number, since it uses as much as digits as its factorization.

21489877909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 374979.

The product of its (nonzero) digits is 18289152, while the sum is 64.

The spelling of 21489877909 in words is "twenty-one billion, four hundred eighty-nine million, eight hundred seventy-seven thousand, nine hundred nine".