1961663 has 4 divisors (see below), whose sum is σ = 2140008. Its totient is φ = 1783320.

The previous prime is 1961657. The next prime is 1961669. The reversal of 1961663 is 3661691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3661691 = 11 ⋅332881.

It is an interprime number because it is at equal distance from previous prime (1961657) and next prime (1961669).

It is not a de Polignac number, because 1961663 - 2¹⁰ = 1960639 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1961669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89156 + ... + 89177.

It is an arithmetic number, because the mean of its divisors is an integer number (535002).

2^1961663 is an apocalyptic number.

1961663 is a deficient number, since it is larger than the sum of its proper divisors (178345).

1961663 is a wasteful number, since it uses less digits than its factorization.

1961663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178344.

The product of its digits is 5832, while the sum is 32.

The square root of 1961663 is about 1400.5938026423. The cubic root of 1961663 is about 125.1818792312.

The spelling of 1961663 in words is "one million, nine hundred sixty-one thousand, six hundred sixty-three".