1321725820 has 48 divisors (see below), whose sum is σ = 2904955200. Its totient is φ = 504193536.

The previous prime is 1321725799. The next prime is 1321725871. The reversal of 1321725820 is 285271231.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 156424 + ... + 164656.

It is an arithmetic number, because the mean of its divisors is an integer number (60519900).

Almost surely, 2^1321725820 is an apocalyptic number.

1321725820 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 1321725820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1452477600).

1321725820 is an abundant number, since it is smaller than the sum of its proper divisors (1583229380).

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

1321725820 is a wasteful number, since it uses less digits than its factorization.

1321725820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8614 (or 8612 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 1321725820 is about 36355.5473071167. The cubic root of 1321725820 is about 1097.4391724321.

The spelling of 1321725820 in words is "one billion, three hundred twenty-one million, seven hundred twenty-five thousand, eight hundred twenty".