19961660101 has 4 divisors (see below), whose sum is σ = 20011440204. Its totient is φ = 19911880000.

The previous prime is 19961660063. The next prime is 19961660137. The reversal of 19961660101 is 10106616991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10106616991 = 1297 ⋅7792303.

It can be written as a sum of positive squares in 2 ways, for example, as 19600280001 + 361380100 = 140001^2 + 19010^2 .

It is a cyclic number.

It is not a de Polignac number, because 19961660101 - 2²⁵ = 19928105669 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 (19961663101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24889450 + ... + 24890251.

It is an arithmetic number, because the mean of its divisors is an integer number (5002860051).

Almost surely, 2^19961660101 is an apocalyptic number.

It is an amenable number.

19961660101 is a deficient number, since it is larger than the sum of its proper divisors (49780103).

19961660101 is an equidigital number, since it uses as much as digits as its factorization.

19961660101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49780102.

The product of its (nonzero) digits is 17496, while the sum is 40.

The spelling of 19961660101 in words is "nineteen billion, nine hundred sixty-one million, six hundred sixty thousand, one hundred one".