778551161 has 4 divisors (see below), whose sum is σ = 783213312. Its totient is φ = 773889012.

The previous prime is 778551149. The next prime is 778551181. The reversal of 778551161 is 161155877.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 161155877 = 9239 ⋅17443.

It is a cyclic number.

It is not a de Polignac number, because 778551161 - 2⁶ = 778551097 is a prime.

It is a super-2 number, since 2×778551161² = 1212283820588895842, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (778551181) 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, 2330825 + ... + 2331158.

It is an arithmetic number, because the mean of its divisors is an integer number (195803328).

Almost surely, 2^778551161 is an apocalyptic number.

It is an amenable number.

778551161 is a deficient number, since it is larger than the sum of its proper divisors (4662151).

778551161 is a wasteful number, since it uses less digits than its factorization.

778551161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4662150.

The product of its digits is 58800, while the sum is 41.

The square root of 778551161 is about 27902.5296523451. The cubic root of 778551161 is about 919.9461062475.

The spelling of 778551161 in words is "seven hundred seventy-eight million, five hundred fifty-one thousand, one hundred sixty-one".