1961605 has 4 divisors (see below), whose sum is σ = 2353932. Its totient is φ = 1569280.

The previous prime is 1961593. The next prime is 1961623. The reversal of 1961605 is 5061691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5061691 = 191 ⋅26501.

It can be written as a sum of positive squares in 2 ways, for example, as 1324801 + 636804 = 1151^2 + 798^2 .

It is not a de Polignac number, because 1961605 - 2⁹ = 1961093 is a prime.

It is a Duffinian number.

1961605 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 (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 196156 + ... + 196165.

It is an arithmetic number, because the mean of its divisors is an integer number (588483).

2^1961605 is an apocalyptic number.

It is an amenable number.

1961605 is a deficient number, since it is larger than the sum of its proper divisors (392327).

1961605 is an equidigital number, since it uses as much as digits as its factorization.

1961605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392326.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 1961605 is about 1400.5730969857. The cubic root of 1961605 is about 125.1806454786.

The spelling of 1961605 in words is "one million, nine hundred sixty-one thousand, six hundred five".