77721689564 has 24 divisors (see below), whose sum is σ = 146042090208. Its totient is φ = 36059770880.

The previous prime is 77721689561. The next prime is 77721689621. The reversal of 77721689564 is 46598612777.

It is a super-2 number, since 2×77721689564² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 77721689497 and 77721689506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77721689561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8044229 + ... + 8053884.

It is an arithmetic number, because the mean of its divisors is an integer number (6085087092).

Almost surely, 2^77721689564 is an apocalyptic number.

It is an amenable number.

77721689564 is a deficient number, since it is larger than the sum of its proper divisors (68320400644).

77721689564 is a wasteful number, since it uses less digits than its factorization.

77721689564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16098205 (or 16098203 counting only the distinct ones).

The product of its digits is 35562240, while the sum is 62.

The spelling of 77721689564 in words is "seventy-seven billion, seven hundred twenty-one million, six hundred eighty-nine thousand, five hundred sixty-four".