1221644120 has 16 divisors (see below), whose sum is σ = 2748699360. Its totient is φ = 488657632.

The previous prime is 1221644119. The next prime is 1221644131. The reversal of 1221644120 is 214461221.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15270512 + ... + 15270591.

It is an arithmetic number, because the mean of its divisors is an integer number (171793710).

Almost surely, 2^1221644120 is an apocalyptic number.

1221644120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221644120 is an abundant number, since it is smaller than the sum of its proper divisors (1527055240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221644120 is a wasteful number, since it uses less digits than its factorization.

1221644120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30541114 (or 30541110 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 1221644120 is about 34952.0259784751. The cubic root of 1221644120 is about 1069.0095122572.

The spelling of 1221644120 in words is "one billion, two hundred twenty-one million, six hundred forty-four thousand, one hundred twenty".