21102120001 has 8 divisors (see below), whose sum is σ = 21547340424. Its totient is φ = 20661120000.

The previous prime is 21102119993. The next prime is 21102120041. The reversal of 21102120001 is 10002120112.

It can be written as a sum of positive squares in 4 ways, for example, as 1430654976 + 19671465025 = 37824^2 + 140255^2 .

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 21102120001 - 2³ = 21102119993 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21102120001.

It is not an unprimeable number, because it can be changed into a prime (21102120041) 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, 1045000 + ... + 1065001.

It is an arithmetic number, because the mean of its divisors is an integer number (2693417553).

Almost surely, 2^21102120001 is an apocalyptic number.

It is an amenable number.

21102120001 is a deficient number, since it is larger than the sum of its proper divisors (445220423).

21102120001 is a wasteful number, since it uses less digits than its factorization.

21102120001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2110211.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21102120001 its reverse (10002120112), we get a palindrome (31104240113).

The spelling of 21102120001 in words is "twenty-one billion, one hundred two million, one hundred twenty thousand, one".