1775221897 has 2 divisors, whose sum is σ = 1775221898. Its totient is φ = 1775221896.

The previous prime is 1775221879. The next prime is 1775221901. The reversal of 1775221897 is 7981225771.

Together with previous prime (1775221879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1746320521 + 28901376 = 41789^2 + 5376^2 .

It is an emirp because it is prime and its reverse (7981225771) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1775221897 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1775221897.

It is not a weakly prime, because it can be changed into another prime (1775221807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 887610948 + 887610949.

It is an arithmetic number, because the mean of its divisors is an integer number (887610949).

Almost surely, 2^1775221897 is an apocalyptic number.

It is an amenable number.

1775221897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1775221897 is an equidigital number, since it uses as much as digits as its factorization.

1775221897 is an evil number, because the sum of its binary digits is even.

The product of its digits is 493920, while the sum is 49.

The square root of 1775221897 is about 42133.3822164801. The cubic root of 1775221897 is about 1210.8329071708.

The spelling of 1775221897 in words is "one billion, seven hundred seventy-five million, two hundred twenty-one thousand, eight hundred ninety-seven".