1566561 has 8 divisors (see below), whose sum is σ = 2095200. Its totient is φ = 1041152.

The previous prime is 1566559. The next prime is 1566571. The reversal of 1566561 is 1656651.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1566561 - 2¹ = 1566559 is a prime.

It is a super-2 number, since 2×1566561² = 4908226733442, which contains 22 as substring.

1566561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1566571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 766 + ... + 1928.

It is an arithmetic number, because the mean of its divisors is an integer number (261900).

2^1566561 is an apocalyptic number.

It is an amenable number.

1566561 is a deficient number, since it is larger than the sum of its proper divisors (528639).

1566561 is a wasteful number, since it uses less digits than its factorization.

1566561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1615.

The product of its digits is 5400, while the sum is 30.

The square root of 1566561 is about 1251.6233458992. The cubic root of 1566561 is about 116.1401644968.

The spelling of 1566561 in words is "one million, five hundred sixty-six thousand, five hundred sixty-one".