1581216000 has 576 divisors, whose sum is σ = 6499723776. Its totient is φ = 331776000.

The previous prime is 1581215947. The next prime is 1581216001. The reversal of 1581216000 is 6121851.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (1581216001) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8735910 + ... + 8736090.

Almost surely, 2^1581216000 is an apocalyptic number.

1581216000 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 1581216000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3249861888).

1581216000 is an abundant number, since it is smaller than the sum of its proper divisors (4918507776).

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

1581216000 is a wasteful number, since it uses less digits than its factorization.

1581216000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 235 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 24.

The square root of 1581216000 is about 39764.5067868319. The cubic root of 1581216000 is about 1165.0120035357.

Adding to 1581216000 its reverse (6121851), we get a palindrome (1587337851).

The spelling of 1581216000 in words is "one billion, five hundred eighty-one million, two hundred sixteen thousand".