1221010221 has 8 divisors (see below), whose sum is σ = 1654702624. Its totient is φ = 800662320.

The previous prime is 1221010213. The next prime is 1221010247. The reversal of 1221010221 is 1220101221.

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

It is not a de Polignac number, because 1221010221 - 2³ = 1221010213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221010197 and 1221010206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221010201) 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, 3335911 + ... + 3336276.

It is an arithmetic number, because the mean of its divisors is an integer number (206837828).

Almost surely, 2^1221010221 is an apocalyptic number.

It is an amenable number.

1221010221 is a deficient number, since it is larger than the sum of its proper divisors (433692403).

1221010221 is an equidigital number, since it uses as much as digits as its factorization.

1221010221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6672251.

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

The square root of 1221010221 is about 34942.9566722680. The cubic root of 1221010221 is about 1068.8245807945.

Adding to 1221010221 its reverse (1220101221), we get a palindrome (2441111442).

The spelling of 1221010221 in words is "one billion, two hundred twenty-one million, ten thousand, two hundred twenty-one".