1221012121 has 8 divisors (see below), whose sum is σ = 1407792384. Its totient is φ = 1037319360.

The previous prime is 1221012119. The next prime is 1221012137. The reversal of 1221012121 is 1212101221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221012121 - 2¹ = 1221012119 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221012421) 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, 771025 + ... + 772606.

It is an arithmetic number, because the mean of its divisors is an integer number (175974048).

Almost surely, 2^1221012121 is an apocalyptic number.

It is an amenable number.

1221012121 is a deficient number, since it is larger than the sum of its proper divisors (186780263).

1221012121 is a wasteful number, since it uses less digits than its factorization.

1221012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1543751.

The product of its (nonzero) digits is 16, while the sum is 13.

The square root of 1221012121 is about 34942.9838594245. The cubic root of 1221012121 is about 1068.8251351894.

Adding to 1221012121 its reverse (1212101221), we get a palindrome (2433113342).

It can be divided in two parts, 12210 and 12121, that multiplied together give a triangular number (147997410 = T₁₇₂₀₄).

The spelling of 1221012121 in words is "one billion, two hundred twenty-one million, twelve thousand, one hundred twenty-one".