1221315680 has 216 divisors, whose sum is σ = 3297109536. Its totient is φ = 427115520.

The previous prime is 1221315677. The next prime is 1221315691. The reversal of 1221315680 is 865131221.

It is a super-2 number, since 2×1221315680² = 2983223980427724800, which contains 22 as substring.

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 35 ways as a sum of consecutive naturals, for example, 25985417 + ... + 25985463.

It is an arithmetic number, because the mean of its divisors is an integer number (15264396).

Almost surely, 2^1221315680 is an apocalyptic number.

1221315680 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 1221315680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1648554768).

1221315680 is an abundant number, since it is smaller than the sum of its proper divisors (2075793856).

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

1221315680 is a wasteful number, since it uses less digits than its factorization.

1221315680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 1221315680 is about 34947.3272225502. The cubic root of 1221315680 is about 1068.9137023161.

The spelling of 1221315680 in words is "one billion, two hundred twenty-one million, three hundred fifteen thousand, six hundred eighty".