1821616 has 20 divisors (see below), whose sum is σ = 3551112. Its totient is φ = 905216.

The previous prime is 1821613. The next prime is 1821641. The reversal of 1821616 is 6161281.

It is a super-3 number, since 3×1821616³ = 18133922333909618688, which contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (1821613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3891 + ... + 4333.

2^1821616 is an apocalyptic number.

1821616 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1821616 is a deficient number, since it is larger than the sum of its proper divisors (1729496).

1821616 is a wasteful number, since it uses less digits than its factorization.

1821616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708 (or 702 counting only the distinct ones).

The product of its digits is 576, while the sum is 25.

The square root of 1821616 is about 1349.6725528809. The cubic root of 1821616 is about 122.1290402098.

Adding to 1821616 its reverse (6161281), we get a palindrome (7982897).

The spelling of 1821616 in words is "one million, eight hundred twenty-one thousand, six hundred sixteen".