1961954261 has 2 divisors, whose sum is σ = 1961954262. Its totient is φ = 1961954260.

The previous prime is 1961954237. The next prime is 1961954273. The reversal of 1961954261 is 1624591691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1933800625 + 28153636 = 43975^2 + 5306^2 .

It is an emirp because it is prime and its reverse (1624591691) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1961954261 is a prime.

It is a super-2 number, since 2×1961954261² = 7698529044512112242, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1961954201) 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 as a sum of consecutive naturals, namely, 980977130 + 980977131.

It is an arithmetic number, because the mean of its divisors is an integer number (980977131).

Almost surely, 2^1961954261 is an apocalyptic number.

It is an amenable number.

1961954261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1961954261 is an equidigital number, since it uses as much as digits as its factorization.

1961954261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 116640, while the sum is 44.

The square root of 1961954261 is about 44293.9528716957. The cubic root of 1961954261 is about 1251.8807445009.

The spelling of 1961954261 in words is "one billion, nine hundred sixty-one million, nine hundred fifty-four thousand, two hundred sixty-one".