77864214581 has 4 divisors (see below), whose sum is σ = 77867053164. Its totient is φ = 77861376000.

The previous prime is 77864214563. The next prime is 77864214587. The reversal of 77864214581 is 18541246877.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18541246877 = 17 ⋅1090661581.

It can be written as a sum of positive squares in 2 ways, for example, as 9455812081 + 68408402500 = 97241^2 + 261550^2 .

It is a cyclic number.

It is not a de Polignac number, because 77864214581 - 2³⁰ = 76790472757 is a prime.

It is a super-2 number, since 2×77864214581² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77864214587) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1377740 + ... + 1433141.

It is an arithmetic number, because the mean of its divisors is an integer number (19466763291).

Almost surely, 2^77864214581 is an apocalyptic number.

It is an amenable number.

77864214581 is a deficient number, since it is larger than the sum of its proper divisors (2838583).

77864214581 is a wasteful number, since it uses less digits than its factorization.

77864214581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2838582.

The product of its digits is 3010560, while the sum is 53.

The spelling of 77864214581 in words is "seventy-seven billion, eight hundred sixty-four million, two hundred fourteen thousand, five hundred eighty-one".