77721064 has 16 divisors (see below), whose sum is σ = 145847520. Its totient is φ = 38828400.

The previous prime is 77721047. The next prime is 77721067. The reversal of 77721064 is 46012777.

It is not an unprimeable number, because it can be changed into a prime (77721067) 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, 8589 + ... + 15139.

It is an arithmetic number, because the mean of its divisors is an integer number (9115470).

Almost surely, 2^77721064 is an apocalyptic number.

It is an amenable number.

77721064 is a deficient number, since it is larger than the sum of its proper divisors (68126456).

77721064 is a wasteful number, since it uses less digits than its factorization.

77721064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8040 (or 8036 counting only the distinct ones).

The product of its (nonzero) digits is 16464, while the sum is 34.

The square root of 77721064 is about 8815.9550815553. The cubic root of 77721064 is about 426.7559443170.

It can be divided in two parts, 7772 and 1064, that added together give a square (8836 = 94²).

The spelling of 77721064 in words is "seventy-seven million, seven hundred twenty-one thousand, sixty-four".