1561216 has 16 divisors (see below), whose sum is σ = 3110490. Its totient is φ = 780544.

The previous prime is 1561213. The next prime is 1561243. The reversal of 1561216 is 6121651.

It can be written as a sum of positive squares in only one way, i.e., 1201216 + 360000 = 1096^2 + 600^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (1561213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5971 + ... + 6226.

2^1561216 is an apocalyptic number.

1561216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1561216 is a deficient number, since it is larger than the sum of its proper divisors (1549274).

1561216 is an equidigital number, since it uses as much as digits as its factorization.

1561216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12211 (or 12199 counting only the distinct ones).

The product of its digits is 360, while the sum is 22.

The square root of 1561216 is about 1249.4862944426. The cubic root of 1561216 is about 116.0079265293.

Adding to 1561216 its reverse (6121651), we get a palindrome (7682867).

The spelling of 1561216 in words is "one million, five hundred sixty-one thousand, two hundred sixteen".