19561841 has 4 divisors (see below), whose sum is σ = 21066612. Its totient is φ = 18057072.

The previous prime is 19561831. The next prime is 19561859. The reversal of 19561841 is 14816591.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 14816591 = 73 ⋅202967.

It can be written as a sum of positive squares in 2 ways, for example, as 12931216 + 6630625 = 3596^2 + 2575^2 .

It is a cyclic number.

It is not a de Polignac number, because 19561841 - 2⁶ = 19561777 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19561831) 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, 752366 + ... + 752391.

It is an arithmetic number, because the mean of its divisors is an integer number (5266653).

Almost surely, 2^19561841 is an apocalyptic number.

It is an amenable number.

19561841 is a deficient number, since it is larger than the sum of its proper divisors (1504771).

19561841 is a wasteful number, since it uses less digits than its factorization.

19561841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1504770.

The product of its digits is 8640, while the sum is 35.

The square root of 19561841 is about 4422.8770048465. The cubic root of 19561841 is about 269.4448630438. Note that the first 3 decimals are identical.

It can be divided in two parts, 19561 and 841, that added together give a palindrome (20402).

The spelling of 19561841 in words is "nineteen million, five hundred sixty-one thousand, eight hundred forty-one".