10001212121221 has 4 divisors (see below), whose sum is σ = 10001406178944. Its totient is φ = 10001018063500.

The previous prime is 10001212121207. The next prime is 10001212121233. The reversal of 10001212121221 is 12212121210001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 10001212121221 - 2¹⁵ = 10001212088453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 10001212121195 and 10001212121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (10001212124221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 96951535 + ... + 97054636.

It is an arithmetic number, because the mean of its divisors is an integer number (2500351544736).

Almost surely, 2^{10001212121221} is an apocalyptic number.

It is an amenable number.

10001212121221 is a deficient number, since it is larger than the sum of its proper divisors (194057723).

10001212121221 is an equidigital number, since it uses as much as digits as its factorization.

10001212121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194057722.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 10001212121221 its reverse (12212121210001), we get a palindrome (22213333331222).

The spelling of 10001212121221 in words is "ten trillion, one billion, two hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".