210109009921 has 8 divisors (see below), whose sum is σ = 210851812584. Its totient is φ = 209366382720.

The previous prime is 210109009919. The next prime is 210109009937. The reversal of 210109009921 is 129900901012.

It can be written as a sum of positive squares in 4 ways, for example, as 12738508225 + 197370501696 = 112865^2 + 444264^2 .

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 210109009921 - 2¹ = 210109009919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (210109009961) 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, 2645035 + ... + 2723311.

It is an arithmetic number, because the mean of its divisors is an integer number (26356476573).

Almost surely, 2^210109009921 is an apocalyptic number.

It is an amenable number.

210109009921 is a deficient number, since it is larger than the sum of its proper divisors (742802663).

210109009921 is an equidigital number, since it uses as much as digits as its factorization.

210109009921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87731.

The product of its (nonzero) digits is 2916, while the sum is 34.

The spelling of 210109009921 in words is "two hundred ten billion, one hundred nine million, nine thousand, nine hundred twenty-one".