1821311648 has 72 divisors (see below), whose sum is σ = 3947114556. Its totient is φ = 826675200.

The previous prime is 1821311647. The next prime is 1821311683. The reversal of 1821311648 is 8461131281.

It can be written as a sum of positive squares in 6 ways, for example, as 753424 + 1820558224 = 868^2 + 42668^2 .

It is a super-2 number, since 2×1821311648² = 6634352238280951808, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1821311641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 327128 + ... + 332648.

Almost surely, 2^1821311648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1821311648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1973557278).

1821311648 is an abundant number, since it is smaller than the sum of its proper divisors (2125802908).

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

1821311648 is a wasteful number, since it uses less digits than its factorization.

1821311648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5618 (or 5597 counting only the distinct ones).

The product of its digits is 9216, while the sum is 35.

The square root of 1821311648 is about 42676.8279983412. The cubic root of 1821311648 is about 1221.2223813809. Note that the first 3 decimals are identical.

The spelling of 1821311648 in words is "one billion, eight hundred twenty-one million, three hundred eleven thousand, six hundred forty-eight".