65721312 has 36 divisors (see below), whose sum is σ = 186895800. Its totient is φ = 21907008.

The previous prime is 65721307. The next prime is 65721317. The reversal of 65721312 is 21312756.

It is a happy number.

65721312 is a `hidden beast` number, since 657 + 2 + 1 + 3 + 1 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (65721307) and next prime (65721317).

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65721317) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 113812 + ... + 114387.

It is an arithmetic number, because the mean of its divisors is an integer number (5191550).

Almost surely, 2^65721312 is an apocalyptic number.

It is an amenable number.

65721312 is an abundant number, since it is smaller than the sum of its proper divisors (121174488).

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

65721312 is a wasteful number, since it uses less digits than its factorization.

65721312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 228215 (or 228204 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 65721312 is about 8106.8681992493. The cubic root of 65721312 is about 403.5543889132.

The spelling of 65721312 in words is "sixty-five million, seven hundred twenty-one thousand, three hundred twelve".