1287777221 has 2 divisors, whose sum is σ = 1287777222. Its totient is φ = 1287777220.

The previous prime is 1287777187. The next prime is 1287777229. The reversal of 1287777221 is 1227777821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1245384100 + 42393121 = 35290^2 + 6511^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1287777221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1287777229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 643888610 + 643888611.

It is an arithmetic number, because the mean of its divisors is an integer number (643888611).

Almost surely, 2^1287777221 is an apocalyptic number.

It is an amenable number.

1287777221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1287777221 is an equidigital number, since it uses as much as digits as its factorization.

1287777221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 153664, while the sum is 44.

The square root of 1287777221 is about 35885.6130085582. The cubic root of 1287777221 is about 1087.9616313986.

The spelling of 1287777221 in words is "one billion, two hundred eighty-seven million, seven hundred seventy-seven thousand, two hundred twenty-one".