21010312109 has 8 divisors (see below), whose sum is σ = 21736663320. Its totient is φ = 20284084800.

The previous prime is 21010312091. The next prime is 21010312133. The reversal of 21010312109 is 90121301012.

It can be written as a sum of positive squares in 4 ways, for example, as 16929913225 + 4080398884 = 130115^2 + 63878^2 .

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

It is not a de Polignac number, because 21010312109 - 2¹² = 21010308013 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 (21010312009) 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, 431039 + ... + 477299.

It is an arithmetic number, because the mean of its divisors is an integer number (2717082915).

Almost surely, 2^21010312109 is an apocalyptic number.

21010312109 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21010312109 is a deficient number, since it is larger than the sum of its proper divisors (726351211).

21010312109 is a wasteful number, since it uses less digits than its factorization.

21010312109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61951.

The product of its (nonzero) digits is 108, while the sum is 20.

The spelling of 21010312109 in words is "twenty-one billion, ten million, three hundred twelve thousand, one hundred nine".