1261605 has 16 divisors (see below), whose sum is σ = 2035584. Its totient is φ = 667200.

The previous prime is 1261571. The next prime is 1261627. The reversal of 1261605 is 5061621.

It is a happy number.

It is not a de Polignac number, because 1261605 - 2¹⁵ = 1228837 is a prime.

It is a Curzon number.

1261605 is a lucky number.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1987 + ... + 2543.

It is an arithmetic number, because the mean of its divisors is an integer number (127224).

2^1261605 is an apocalyptic number.

1261605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1261605 is a deficient number, since it is larger than the sum of its proper divisors (773979).

1261605 is a wasteful number, since it uses less digits than its factorization.

1261605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 716.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 1261605 is about 1123.2119123300. The cubic root of 1261605 is about 108.0540710040.

The spelling of 1261605 in words is "one million, two hundred sixty-one thousand, six hundred five".