21398744209 has 8 divisors (see below), whose sum is σ = 22379539392. Its totient is φ = 20422150320.

The previous prime is 21398744207. The next prime is 21398744233. The reversal of 21398744209 is 90244789312.

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 21398744209 - 2¹ = 21398744207 is a prime.

It is a super-2 number, since 2×21398744209² (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 (21398744207) 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, 1039902 + ... + 1060279.

It is an arithmetic number, because the mean of its divisors is an integer number (2797442424).

Almost surely, 2^21398744209 is an apocalyptic number.

It is an amenable number.

21398744209 is a deficient number, since it is larger than the sum of its proper divisors (980795183).

21398744209 is a wasteful number, since it uses less digits than its factorization.

21398744209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2100647.

The product of its (nonzero) digits is 870912, while the sum is 49.

The spelling of 21398744209 in words is "twenty-one billion, three hundred ninety-eight million, seven hundred forty-four thousand, two hundred nine".