21212110009 has 8 divisors (see below), whose sum is σ = 22492397088. Its totient is φ = 19935435840.

The previous prime is 21212109967. The next prime is 21212110013. The reversal of 21212110009 is 90001121212.

It is a happy number.

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 21212110009 - 2⁹ = 21212109497 is a prime.

It is a super-3 number, since 3×21212110009³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212110109) 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, 891127 + ... + 914620.

It is an arithmetic number, because the mean of its divisors is an integer number (2811549636).

Almost surely, 2^21212110009 is an apocalyptic number.

It is an amenable number.

21212110009 is a deficient number, since it is larger than the sum of its proper divisors (1280287079).

21212110009 is a wasteful number, since it uses less digits than its factorization.

21212110009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1806455.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 21212110009 in words is "twenty-one billion, two hundred twelve million, one hundred ten thousand, nine".