65811920 has 30 divisors (see below), whose sum is σ = 153181602. Its totient is φ = 26295744.

The previous prime is 65811919. The next prime is 65811931. The reversal of 65811920 is 2911856.

It can be written as a sum of positive squares in only one way, i.e., 52649536 + 13162384 = 7256^2 + 3628^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 72107 + ... + 73013.

Almost surely, 2^65811920 is an apocalyptic number.

It is an amenable number.

65811920 is an abundant number, since it is smaller than the sum of its proper divisors (87369682).

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

65811920 is an frugal number, since it uses more digits than its factorization.

65811920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1827 (or 914 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 65811920 is about 8112.4546223692. The cubic root of 65811920 is about 403.7397598581.

The spelling of 65811920 in words is "sixty-five million, eight hundred eleven thousand, nine hundred twenty".