77012820 has 36 divisors (see below), whose sum is σ = 233606100. Its totient is φ = 20536704.

The previous prime is 77012807. The next prime is 77012849. The reversal of 77012820 is 2821077.

It can be written as a sum of positive squares in 2 ways, for example, as 48944016 + 28068804 = 6996^2 + 5298^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 213745 + ... + 214104.

Almost surely, 2^77012820 is an apocalyptic number.

It is an amenable number.

77012820 is an abundant number, since it is smaller than the sum of its proper divisors (156593280).

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

77012820 is a wasteful number, since it uses less digits than its factorization.

77012820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427864 (or 427859 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 27.

The square root of 77012820 is about 8775.6948442844. The cubic root of 77012820 is about 425.4556957612.

Adding to 77012820 its reverse (2821077), we get a palindrome (79833897).

The spelling of 77012820 in words is "seventy-seven million, twelve thousand, eight hundred twenty".