1961241857 has 2 divisors, whose sum is σ = 1961241858. Its totient is φ = 1961241856.

The previous prime is 1961241817. The next prime is 1961241859. The reversal of 1961241857 is 7581421691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1248138241 + 713103616 = 35329^2 + 26704^2 .

It is an emirp because it is prime and its reverse (7581421691) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1961241857 is a prime.

Together with 1961241859, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1961241859) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 980620928 + 980620929.

It is an arithmetic number, because the mean of its divisors is an integer number (980620929).

Almost surely, 2^1961241857 is an apocalyptic number.

It is an amenable number.

1961241857 is a deficient number, since it is larger than the sum of its proper divisors (1).

1961241857 is an equidigital number, since it uses as much as digits as its factorization.

1961241857 is an evil number, because the sum of its binary digits is even.

The product of its digits is 120960, while the sum is 44.

The square root of 1961241857 is about 44285.9103666166. The cubic root of 1961241857 is about 1251.7292029427.

The spelling of 1961241857 in words is "one billion, nine hundred sixty-one million, two hundred forty-one thousand, eight hundred fifty-seven".