65291991 has 8 divisors (see below), whose sum is σ = 87160320. Its totient is φ = 43475832.

The previous prime is 65291971. The next prime is 65292043. The reversal of 65291991 is 19919256.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 65291991 - 2⁶ = 65291927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65291971) 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, 10021 + ... + 15198.

It is an arithmetic number, because the mean of its divisors is an integer number (10895040).

Almost surely, 2^65291991 is an apocalyptic number.

65291991 is a deficient number, since it is larger than the sum of its proper divisors (21868329).

65291991 is a wasteful number, since it uses less digits than its factorization.

65291991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26085.

The product of its digits is 43740, while the sum is 42.

The square root of 65291991 is about 8080.3459703159. The cubic root of 65291991 is about 402.6737359358.

The spelling of 65291991 in words is "sixty-five million, two hundred ninety-one thousand, nine hundred ninety-one".