21195170209 has 8 divisors (see below), whose sum is σ = 21248892000. Its totient is φ = 21141494400.

The previous prime is 21195170203. The next prime is 21195170233. The reversal of 21195170209 is 90207159112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21195170209 is a prime.

It is a super-2 number, since 2×21195170209² (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 (21195170203) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1028214 + ... + 1048624.

It is an arithmetic number, because the mean of its divisors is an integer number (2656111500).

Almost surely, 2^21195170209 is an apocalyptic number.

It is an amenable number.

21195170209 is a deficient number, since it is larger than the sum of its proper divisors (53721791).

21195170209 is a wasteful number, since it uses less digits than its factorization.

21195170209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22991.

The product of its (nonzero) digits is 11340, while the sum is 37.

The spelling of 21195170209 in words is "twenty-one billion, one hundred ninety-five million, one hundred seventy thousand, two hundred nine".