8405561 has 4 divisors (see below), whose sum is σ = 8448000. Its totient is φ = 8363124.

The previous prime is 8405519. The next prime is 8405567. The reversal of 8405561 is 1655048.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8405561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8405567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20921 + ... + 21318.

It is an arithmetic number, because the mean of its divisors is an integer number (2112000).

Almost surely, 2^8405561 is an apocalyptic number.

It is an amenable number.

8405561 is a deficient number, since it is larger than the sum of its proper divisors (42439).

8405561 is a wasteful number, since it uses less digits than its factorization.

8405561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42438.

The product of its (nonzero) digits is 4800, while the sum is 29.

The square root of 8405561 is about 2899.2345541539. The cubic root of 8405561 is about 203.3241200400.

The spelling of 8405561 in words is "eight million, four hundred five thousand, five hundred sixty-one".