1561605 has 8 divisors (see below), whose sum is σ = 2498592. Its totient is φ = 832848.

The previous prime is 1561601. The next prime is 1561607. The reversal of 1561605 is 5061651.

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

It is not a de Polignac number, because 1561605 - 2² = 1561601 is a prime.

It is a super-2 number, since 2×1561605² = 4877220352050, which contains 22 as substring.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52039 + ... + 52068.

It is an arithmetic number, because the mean of its divisors is an integer number (312324).

2^1561605 is an apocalyptic number.

1561605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1561605 is a deficient number, since it is larger than the sum of its proper divisors (936987).

1561605 is a wasteful number, since it uses less digits than its factorization.

1561605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104115.

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 1561605 is about 1249.6419487197. The cubic root of 1561605 is about 116.0175607580.

The spelling of 1561605 in words is "one million, five hundred sixty-one thousand, six hundred five".