65721912 has 64 divisors (see below), whose sum is σ = 174787200. Its totient is φ = 20534400.

The previous prime is 65721911. The next prime is 65721919. The reversal of 65721912 is 21912756.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65721911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45343 + ... + 46769.

It is an arithmetic number, because the mean of its divisors is an integer number (2731050).

Almost surely, 2^65721912 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 65721912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87393600).

65721912 is an abundant number, since it is smaller than the sum of its proper divisors (109065288).

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

65721912 is a wasteful number, since it uses less digits than its factorization.

65721912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556 (or 1552 counting only the distinct ones).

The product of its digits is 7560, while the sum is 33.

The square root of 65721912 is about 8106.9052048238. The cubic root of 65721912 is about 403.5556169872. Note that the first 3 decimals are identical.

It can be divided in two parts, 657219 and 12, that added together give a triangular number (657231 = T₁₁₄₆).

The spelling of 65721912 in words is "sixty-five million, seven hundred twenty-one thousand, nine hundred twelve".