1321787220 has 48 divisors (see below), whose sum is σ = 3985699200. Its totient is φ = 325362816.

The previous prime is 1321787219. The next prime is 1321787267. The reversal of 1321787220 is 227871231.

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 15 ways as a sum of consecutive naturals, for example, 846520 + ... + 848079.

It is an arithmetic number, because the mean of its divisors is an integer number (83035400).

Almost surely, 2^1321787220 is an apocalyptic number.

1321787220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321787220 is an abundant number, since it is smaller than the sum of its proper divisors (2663911980).

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

1321787220 is a wasteful number, since it uses less digits than its factorization.

1321787220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1694624 (or 1694622 counting only the distinct ones).

The product of its (nonzero) digits is 9408, while the sum is 33.

The square root of 1321787220 is about 36356.3917351544. The cubic root of 1321787220 is about 1097.4561658006.

The spelling of 1321787220 in words is "one billion, three hundred twenty-one million, seven hundred eighty-seven thousand, two hundred twenty".