77721344 has 36 divisors (see below), whose sum is σ = 155924496. Its totient is φ = 38664192.

The previous prime is 77721313. The next prime is 77721359. The reversal of 77721344 is 44312777.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 58997 + ... + 60299.

It is an arithmetic number, because the mean of its divisors is an integer number (4331236).

Almost surely, 2^77721344 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77721344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77962248).

77721344 is an abundant number, since it is smaller than the sum of its proper divisors (78203152).

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

77721344 is a wasteful number, since it uses less digits than its factorization.

77721344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1552 (or 1538 counting only the distinct ones).

The product of its digits is 32928, while the sum is 35.

The square root of 77721344 is about 8815.9709618397. The cubic root of 77721344 is about 426.7564567972.

The spelling of 77721344 in words is "seventy-seven million, seven hundred twenty-one thousand, three hundred forty-four".