77117561 has 4 divisors (see below), whose sum is σ = 81176400. Its totient is φ = 73058724.

The previous prime is 77117549. The next prime is 77117567. The reversal of 77117561 is 16571177.

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.

It is not a de Polignac number, because 77117561 - 2⁶ = 77117497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77117567) 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, 2029391 + ... + 2029428.

It is an arithmetic number, because the mean of its divisors is an integer number (20294100).

Almost surely, 2^77117561 is an apocalyptic number.

It is an amenable number.

77117561 is a deficient number, since it is larger than the sum of its proper divisors (4058839).

77117561 is a wasteful number, since it uses less digits than its factorization.

77117561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4058838.

The product of its digits is 10290, while the sum is 35.

The square root of 77117561 is about 8781.6604921848. The cubic root of 77117561 is about 425.6484881987.

The spelling of 77117561 in words is "seventy-seven million, one hundred seventeen thousand, five hundred sixty-one".