77661018 has 80 divisors (see below), whose sum is σ = 191315520. Its totient is φ = 23436864.

The previous prime is 77660993. The next prime is 77661019. The reversal of 77661018 is 81016677.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (77661019) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 70246 + ... + 71342.

It is an arithmetic number, because the mean of its divisors is an integer number (2391444).

Almost surely, 2^77661018 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77661018, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95657760).

77661018 is an abundant number, since it is smaller than the sum of its proper divisors (113654502).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77661018 is a wasteful number, since it uses less digits than its factorization.

77661018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1153 (or 1144 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 77661018 is about 8812.5488934814. The cubic root of 77661018 is about 426.6460144897.

The spelling of 77661018 in words is "seventy-seven million, six hundred sixty-one thousand, eighteen".