1281958961 has 2 divisors, whose sum is σ = 1281958962. Its totient is φ = 1281958960.

The previous prime is 1281958927. The next prime is 1281958973. The reversal of 1281958961 is 1698591821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1244748961 + 37210000 = 35281^2 + 6100^2 .

It is an emirp because it is prime and its reverse (1698591821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1281958961 - 2¹⁸ = 1281696817 is a prime.

It is not a weakly prime, because it can be changed into another prime (1281958361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640979480 + 640979481.

It is an arithmetic number, because the mean of its divisors is an integer number (640979481).

Almost surely, 2^1281958961 is an apocalyptic number.

It is an amenable number.

1281958961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281958961 is an equidigital number, since it uses as much as digits as its factorization.

1281958961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 311040, while the sum is 50.

The square root of 1281958961 is about 35804.4544854408. The cubic root of 1281958961 is about 1086.3206641257.

The spelling of 1281958961 in words is "one billion, two hundred eighty-one million, nine hundred fifty-eight thousand, nine hundred sixty-one".