1661616 has 60 divisors (see below), whose sum is σ = 5077800. Its totient is φ = 503040.

The previous prime is 1661599. The next prime is 1661623. The reversal of 1661616 is 6161661.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 1661616.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1060 + ... + 2108.

It is an arithmetic number, because the mean of its divisors is an integer number (84630).

2^1661616 is an apocalyptic number.

1661616 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 1661616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2538900).

1661616 is an abundant number, since it is smaller than the sum of its proper divisors (3416184).

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

1661616 is a wasteful number, since it uses less digits than its factorization.

1661616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1074 (or 1065 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 1661616 is about 1289.0368497448. The cubic root of 1661616 is about 118.4432244178.

The spelling of 1661616 in words is "one million, six hundred sixty-one thousand, six hundred sixteen".