65721128 has 32 divisors (see below), whose sum is σ = 135479520. Its totient is φ = 29640000.

The previous prime is 65721121. The next prime is 65721169. The reversal of 65721128 is 82112756.

It is a junction number, because it is equal to n+sod(n) for n = 65721094 and 65721103.

It is not an unprimeable number, because it can be changed into a prime (65721121) 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, 8678 + ... + 14378.

It is an arithmetic number, because the mean of its divisors is an integer number (4233735).

Almost surely, 2^65721128 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 65721128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67739760).

65721128 is an abundant number, since it is smaller than the sum of its proper divisors (69758392).

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

65721128 is a wasteful number, since it uses less digits than its factorization.

65721128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5849 (or 5845 counting only the distinct ones).

The product of its digits is 6720, while the sum is 32.

The square root of 65721128 is about 8106.8568508393. The cubic root of 65721128 is about 403.5540123023.

The spelling of 65721128 in words is "sixty-five million, seven hundred twenty-one thousand, one hundred twenty-eight".