65065991 has 4 divisors (see below), whose sum is σ = 65107800. Its totient is φ = 65024184.

The previous prime is 65065961. The next prime is 65066047. The reversal of 65065991 is 19956056.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65065991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65065921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18476 + ... + 21713.

It is an arithmetic number, because the mean of its divisors is an integer number (16276950).

Almost surely, 2^65065991 is an apocalyptic number.

65065991 is a deficient number, since it is larger than the sum of its proper divisors (41809).

65065991 is a wasteful number, since it uses less digits than its factorization.

65065991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41808.

The product of its (nonzero) digits is 72900, while the sum is 41.

The square root of 65065991 is about 8066.3492981646. The cubic root of 65065991 is about 402.2085973829.

The spelling of 65065991 in words is "sixty-five million, sixty-five thousand, nine hundred ninety-one".