1981616 has 40 divisors (see below), whose sum is σ = 4728864. Its totient is φ = 783360.

The previous prime is 1981607. The next prime is 1981619. The reversal of 1981616 is 6161891.

It is an Ulam number.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (1981619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 776 + ... + 2136.

2^1981616 is an apocalyptic number.

1981616 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 1981616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2364432).

1981616 is an abundant number, since it is smaller than the sum of its proper divisors (2747248).

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

1981616 is a wasteful number, since it uses less digits than its factorization.

1981616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1389 (or 1383 counting only the distinct ones).

The product of its digits is 2592, while the sum is 32.

The square root of 1981616 is about 1407.6988314267. The cubic root of 1981616 is about 125.6048762763.

The spelling of 1981616 in words is "one million, nine hundred eighty-one thousand, six hundred sixteen".