19961280149 has 2 divisors, whose sum is σ = 19961280150. Its totient is φ = 19961280148.

The previous prime is 19961280139. The next prime is 19961280151. The reversal of 19961280149 is 94108216991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19479784900 + 481495249 = 139570^2 + 21943^2 .

It is a cyclic number.

It is not a de Polignac number, because 19961280149 - 2⁸ = 19961279893 is a prime.

It is a super-2 number, since 2×19961280149² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 19961280151, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 19961280097 and 19961280106.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19961280139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9980640074 + 9980640075.

It is an arithmetic number, because the mean of its divisors is an integer number (9980640075).

Almost surely, 2^19961280149 is an apocalyptic number.

It is an amenable number.

19961280149 is a deficient number, since it is larger than the sum of its proper divisors (1).

19961280149 is an equidigital number, since it uses as much as digits as its factorization.

19961280149 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 279936, while the sum is 50.

The spelling of 19961280149 in words is "nineteen billion, nine hundred sixty-one million, two hundred eighty thousand, one hundred forty-nine".