1212121111001 has 4 divisors (see below), whose sum is σ = 1212424980900. Its totient is φ = 1211817241104.

The previous prime is 1212121110961. The next prime is 1212121111007. The reversal of 1212121111001 is 1001111212121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1009552705225 + 202568405776 = 1004765^2 + 450076^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212121111001 - 2³⁸ = 937243204057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1212121111007) 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, 151928966 + ... + 151936943.

It is an arithmetic number, because the mean of its divisors is an integer number (303106245225).

Almost surely, 2^{1212121111001} is an apocalyptic number.

It is an amenable number.

1212121111001 is a deficient number, since it is larger than the sum of its proper divisors (303869899).

1212121111001 is an equidigital number, since it uses as much as digits as its factorization.

1212121111001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303869898.

The product of its (nonzero) digits is 8, while the sum is 14.

Adding to 1212121111001 its reverse (1001111212121), we get a palindrome (2213232323122).

The spelling of 1212121111001 in words is "one trillion, two hundred twelve billion, one hundred twenty-one million, one hundred eleven thousand, one".