1909661 has 8 divisors (see below), whose sum is σ = 2177784. Its totient is φ = 1658880.

The previous prime is 1909651. The next prime is 1909669. The reversal of 1909661 is 1669091.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2500 + 1907161 = 50^2 + 1381^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 1909661 - 2¹⁴ = 1893277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1909669) 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, 4100 + ... + 4541.

It is an arithmetic number, because the mean of its divisors is an integer number (272223).

2^1909661 is an apocalyptic number.

It is an amenable number.

1909661 is a deficient number, since it is larger than the sum of its proper divisors (268123).

1909661 is a wasteful number, since it uses less digits than its factorization.

1909661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8671.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 1909661 is about 1381.9048447704. The cubic root of 1909661 is about 124.0658036098.

The spelling of 1909661 in words is "one million, nine hundred nine thousand, six hundred sixty-one".