1221002121 has 8 divisors (see below), whose sum is σ = 1629300960. Its totient is φ = 813352352.

The previous prime is 1221002087. The next prime is 1221002141. The reversal of 1221002121 is 1212001221.

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 1221002121 - 2¹⁰ = 1221001097 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221002097 and 1221002106.

It is not an unprimeable number, because it can be changed into a prime (1221002141) 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, 157860 + ... + 165413.

It is an arithmetic number, because the mean of its divisors is an integer number (203662620).

Almost surely, 2^1221002121 is an apocalyptic number.

It is an amenable number.

1221002121 is a deficient number, since it is larger than the sum of its proper divisors (408298839).

1221002121 is a wasteful number, since it uses less digits than its factorization.

1221002121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 324535.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 1221002121 is about 34942.8407688900. The cubic root of 1221002121 is about 1068.8222173149.

Adding to 1221002121 its reverse (1212001221), we get a palindrome (2433003342).

The spelling of 1221002121 in words is "one billion, two hundred twenty-one million, two thousand, one hundred twenty-one".