1561616 has 40 divisors (see below), whose sum is σ = 3523584. Its totient is φ = 656640.

The previous prime is 1561607. The next prime is 1561633. The reversal of 1561616 is 6161651.

1561616 = 23³ + 24³ + ... + 50³.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8081 + ... + 8271.

2^1561616 is an apocalyptic number.

1561616 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 1561616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1761792).

1561616 is an abundant number, since it is smaller than the sum of its proper divisors (1961968).

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

1561616 is a wasteful number, since it uses less digits than its factorization.

1561616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279 (or 273 counting only the distinct ones).

The product of its digits is 1080, while the sum is 26.

The square root of 1561616 is about 1249.6463499727. The cubic root of 1561616 is about 116.0178331679.

The spelling of 1561616 in words is "one million, five hundred sixty-one thousand, six hundred sixteen".