1287733261 has 2 divisors, whose sum is σ = 1287733262. Its totient is φ = 1287733260.

The previous prime is 1287733243. The next prime is 1287733267. The reversal of 1287733261 is 1623377821.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1287733225 + 36 = 35885^2 + 6^2 .

It is a cyclic number.

It is not a de Polignac number, because 1287733261 - 2¹⁹ = 1287208973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1287733267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643866630 + 643866631.

It is an arithmetic number, because the mean of its divisors is an integer number (643866631).

Almost surely, 2^1287733261 is an apocalyptic number.

It is an amenable number.

1287733261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287733261 is an equidigital number, since it uses as much as digits as its factorization.

1287733261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 40.

The square root of 1287733261 is about 35885.0005016023. Note that the first 3 decimals coincide. The cubic root of 1287733261 is about 1087.9492515820.

The spelling of 1287733261 in words is "one billion, two hundred eighty-seven million, seven hundred thirty-three thousand, two hundred sixty-one".