1581216 has 96 divisors (see below), whose sum is σ = 5136768. Its totient is φ = 414720.

The previous prime is 1581211. The next prime is 1581257. The reversal of 1581216 is 6121851.

It is a tau number, because it is divible by the number of its divisors (96).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1581211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8646 + ... + 8826.

It is an arithmetic number, because the mean of its divisors is an integer number (53508).

2^1581216 is an apocalyptic number.

1581216 is a gapful number since it is divisible by the number (16) 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 1581216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2568384).

1581216 is an abundant number, since it is smaller than the sum of its proper divisors (3555552).

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

1581216 is a wasteful number, since it uses less digits than its factorization.

1581216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214 (or 206 counting only the distinct ones).

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

The square root of 1581216 is about 1257.4641147961. The cubic root of 1581216 is about 116.5012003536.

The spelling of 1581216 in words is "one million, five hundred eighty-one thousand, two hundred sixteen".