77021845128 has 36 divisors (see below), whose sum is σ = 208607208615. Its totient is φ = 25673163408.

The previous prime is 77021845111. The next prime is 77021845129. The reversal of 77021845128 is 82154812077.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in only one way, i.e., 38510922564 + 38510922564 = 196242^2 + 196242^2 .

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

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=196242.

It is not an unprimeable number, because it can be changed into a prime (77021845129) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2338551 + ... + 2371257.

Almost surely, 2^77021845128 is an apocalyptic number.

It is an amenable number.

77021845128 is an abundant number, since it is smaller than the sum of its proper divisors (131585363487).

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

77021845128 is an frugal number, since it uses more digits than its factorization.

77021845128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65426 (or 32712 counting only the distinct ones).

The product of its (nonzero) digits is 250880, while the sum is 45.

The spelling of 77021845128 in words is "seventy-seven billion, twenty-one million, eight hundred forty-five thousand, one hundred twenty-eight".