775221002161 has 4 divisors (see below), whose sum is σ = 794128831524. Its totient is φ = 756313172800.

The previous prime is 775221002141. The next prime is 775221002183. The reversal of 775221002161 is 161200122577.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 425585312161 + 349635690000 = 652369^2 + 591300^2 .

It is a cyclic number.

It is not a de Polignac number, because 775221002161 - 2³¹ = 773073518513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (775221002141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9453914620 + ... + 9453914701.

It is an arithmetic number, because the mean of its divisors is an integer number (198532207881).

Almost surely, 2^775221002161 is an apocalyptic number.

It is an amenable number.

775221002161 is a deficient number, since it is larger than the sum of its proper divisors (18907829363).

775221002161 is a wasteful number, since it uses less digits than its factorization.

775221002161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18907829362.

The product of its (nonzero) digits is 11760, while the sum is 34.

The spelling of 775221002161 in words is "seven hundred seventy-five billion, two hundred twenty-one million, two thousand, one hundred sixty-one".