21687024209 has 8 divisors (see below), whose sum is σ = 22912191360. Its totient is φ = 20493679696.

The previous prime is 21687024197. The next prime is 21687024217. The reversal of 21687024209 is 90242078612.

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 21687024209 - 2¹⁶ = 21686958673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21687024269) 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, 7954259 + ... + 7956984.

It is an arithmetic number, because the mean of its divisors is an integer number (2864023920).

Almost surely, 2^21687024209 is an apocalyptic number.

21687024209 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21687024209 is a deficient number, since it is larger than the sum of its proper divisors (1225167151).

21687024209 is a wasteful number, since it uses less digits than its factorization.

21687024209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15911319.

The product of its (nonzero) digits is 96768, while the sum is 41.

The spelling of 21687024209 in words is "twenty-one billion, six hundred eighty-seven million, twenty-four thousand, two hundred nine".