1221204960 has 144 divisors (see below), whose sum is σ = 4176428256. Its totient is φ = 324946944.

The previous prime is 1221204947. The next prime is 1221204973. The reversal of 1221204960 is 694021221.

It is an interprime number because it is at equal distance from previous prime (1221204947) and next prime (1221204973).

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1262397 + ... + 1263363.

It is an arithmetic number, because the mean of its divisors is an integer number (29002974).

Almost surely, 2^1221204960 is an apocalyptic number.

1221204960 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221204960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2088214128).

1221204960 is an abundant number, since it is smaller than the sum of its proper divisors (2955223296).

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

1221204960 is a wasteful number, since it uses less digits than its factorization.

1221204960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1865 (or 1854 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 1221204960 is about 34945.7430883935. The cubic root of 1221204960 is about 1068.8814000747.

The spelling of 1221204960 in words is "one billion, two hundred twenty-one million, two hundred four thousand, nine hundred sixty".