77561216 has 16 divisors (see below), whose sum is σ = 154516740. Its totient is φ = 38780544.

The previous prime is 77561189. The next prime is 77561243. The reversal of 77561216 is 61216577.

It is an interprime number because it is at equal distance from previous prime (77561189) and next prime (77561243).

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 302846 + ... + 303101.

Almost surely, 2^77561216 is an apocalyptic number.

It is an amenable number.

77561216 is a deficient number, since it is larger than the sum of its proper divisors (76955524).

77561216 is an equidigital number, since it uses as much as digits as its factorization.

77561216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 605961 (or 605949 counting only the distinct ones).

The product of its digits is 17640, while the sum is 35.

The square root of 77561216 is about 8806.8845796910. The cubic root of 77561216 is about 426.4631755334.

It can be divided in two parts, 77561 and 216, that added together give a palindrome (77777).

The spelling of 77561216 in words is "seventy-seven million, five hundred sixty-one thousand, two hundred sixteen".