19961611 has 4 divisors (see below), whose sum is σ = 20501152. Its totient is φ = 19422072.

The previous prime is 19961603. The next prime is 19961633. The reversal of 19961611 is 11616991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19961611 - 2³ = 19961603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19961681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 269715 + ... + 269788.

It is an arithmetic number, because the mean of its divisors is an integer number (5125288).

Almost surely, 2^19961611 is an apocalyptic number.

19961611 is a deficient number, since it is larger than the sum of its proper divisors (539541).

19961611 is an equidigital number, since it uses as much as digits as its factorization.

19961611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 539540.

The product of its digits is 2916, while the sum is 34.

The square root of 19961611 is about 4467.8418727614. The cubic root of 19961611 is about 271.2679774589.

The spelling of 19961611 in words is "nineteen million, nine hundred sixty-one thousand, six hundred eleven".