1321956720 has 640 divisors, whose sum is σ = 5699635200. Its totient is φ = 274710528.

The previous prime is 1321956719. The next prime is 1321956731. The reversal of 1321956720 is 276591231.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 9510411 + ... + 9510549.

It is an arithmetic number, because the mean of its divisors is an integer number (8905680).

Almost surely, 2^1321956720 is an apocalyptic number.

1321956720 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 1321956720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2849817600).

1321956720 is an abundant number, since it is smaller than the sum of its proper divisors (4377678480).

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

1321956720 is a wasteful number, since it uses less digits than its factorization.

1321956720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222 (or 210 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 1321956720 is about 36358.7227498437. The cubic root of 1321956720 is about 1097.5030747298.

The spelling of 1321956720 in words is "one billion, three hundred twenty-one million, nine hundred fifty-six thousand, seven hundred twenty".