77777641 has 4 divisors (see below), whose sum is σ = 77795284. Its totient is φ = 77760000.

The previous prime is 77777639. The next prime is 77777647. The reversal of 77777641 is 14677777.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 14677777 = 191 ⋅76847.

It can be written as a sum of positive squares in 2 ways, for example, as 6864400 + 70913241 = 2620^2 + 8421^2 .

It is a 4-Lehmer number, since φ(77777641) divides (77777641-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 77777641 - 2¹ = 77777639 is a prime.

It is a super-2 number, since 2×77777641² = 12098722879049762, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 77777591 and 77777600.

It is not an unprimeable number, because it can be changed into a prime (77777647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4141 + ... + 13141.

It is an arithmetic number, because the mean of its divisors is an integer number (19448821).

Almost surely, 2^77777641 is an apocalyptic number.

It is an amenable number.

77777641 is a deficient number, since it is larger than the sum of its proper divisors (17643).

77777641 is an equidigital number, since it uses as much as digits as its factorization.

77777641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17642.

The product of its digits is 403368, while the sum is 46.

The square root of 77777641 is about 8819.1632823075. The cubic root of 77777641 is about 426.8594714412.

The spelling of 77777641 in words is "seventy-seven million, seven hundred seventy-seven thousand, six hundred forty-one".