77766642 has 40 divisors (see below), whose sum is σ = 174984876. Its totient is φ = 25813728.

The previous prime is 77766641. The next prime is 77766673. The reversal of 77766642 is 24666777.

It can be written as a sum of positive squares in 2 ways, for example, as 74494161 + 3272481 = 8631^2 + 1809^2 .

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (77766641) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 44008 + ... + 45740.

Almost surely, 2^77766642 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77766642, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87492438).

77766642 is an abundant number, since it is smaller than the sum of its proper divisors (97218234).

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

77766642 is a wasteful number, since it uses less digits than its factorization.

77766642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2024 (or 2015 counting only the distinct ones).

The product of its digits is 592704, while the sum is 45.

The square root of 77766642 is about 8818.5396750256. The cubic root of 77766642 is about 426.8393489116.

The spelling of 77766642 in words is "seventy-seven million, seven hundred sixty-six thousand, six hundred forty-two".