19661841 has 6 divisors (see below), whose sum is σ = 28400450. Its totient is φ = 13107888.

The previous prime is 19661821. The next prime is 19661867. The reversal of 19661841 is 14816691.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18740241 + 921600 = 4329^2 + 960^2 .

It is not a de Polignac number, because 19661841 - 2⁶ = 19661777 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19661796 and 19661805.

It is not an unprimeable number, because it can be changed into a prime (19661801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1092316 + ... + 1092333.

Almost surely, 2^19661841 is an apocalyptic number.

It is an amenable number.

19661841 is a deficient number, since it is larger than the sum of its proper divisors (8738609).

19661841 is a wasteful number, since it uses less digits than its factorization.

19661841 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2184655 (or 2184652 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 19661841 is about 4434.1674528597. The cubic root of 19661841 is about 269.9032163401.

It can be divided in two parts, 19661 and 841, that added together give a palindrome (20502).

The spelling of 19661841 in words is "nineteen million, six hundred sixty-one thousand, eight hundred forty-one".