1919561 has 4 divisors (see below), whose sum is σ = 2193792. Its totient is φ = 1645332.

The previous prime is 1919549. The next prime is 1919581. The reversal of 1919561 is 1659191.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1659191 = 37 ⋅44843.

It is a cyclic number.

It is not a de Polignac number, because 1919561 - 2¹⁰ = 1918537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1919581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 137105 + ... + 137118.

It is an arithmetic number, because the mean of its divisors is an integer number (548448).

2^1919561 is an apocalyptic number.

It is an amenable number.

1919561 is a deficient number, since it is larger than the sum of its proper divisors (274231).

1919561 is an equidigital number, since it uses as much as digits as its factorization.

1919561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274230.

The product of its digits is 2430, while the sum is 32.

The square root of 1919561 is about 1385.4822265190. The cubic root of 1919561 is about 124.2798267726.

The spelling of 1919561 in words is "one million, nine hundred nineteen thousand, five hundred sixty-one".