1320920640 has 168 divisors, whose sum is σ = 4893048888. Its totient is φ = 325140480.

The previous prime is 1320920617. The next prime is 1320920647. The reversal of 1320920640 is 460290231.

1320920640 is a `hidden beast` number, since 13 + 2 + 0 + 9 + 2 + 0 + 640 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2359296 + 1318561344 = 1536^2 + 36312^2 .

It is not an unprimeable number, because it can be changed into a prime (1320920647) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19800 + ... + 55080.

It is an arithmetic number, because the mean of its divisors is an integer number (29125291).

Almost surely, 2^1320920640 is an apocalyptic number.

1320920640 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 1320920640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2446524444).

1320920640 is an abundant number, since it is smaller than the sum of its proper divisors (3572128248).

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

1320920640 is a wasteful number, since it uses less digits than its factorization.

1320920640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35317 (or 35304 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 1320920640 is about 36344.4719317808. The cubic root of 1320920640 is about 1097.2162781037.

The spelling of 1320920640 in words is "one billion, three hundred twenty million, nine hundred twenty thousand, six hundred forty".