65361991 has 4 divisors (see below), whose sum is σ = 69206832. Its totient is φ = 61517152.

The previous prime is 65361977. The next prime is 65362009. The reversal of 65361991 is 19916356.

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

It is not a de Polignac number, because 65361991 - 2⁹ = 65361479 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65361931) 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, 1922395 + ... + 1922428.

It is an arithmetic number, because the mean of its divisors is an integer number (17301708).

Almost surely, 2^65361991 is an apocalyptic number.

65361991 is a deficient number, since it is larger than the sum of its proper divisors (3844841).

65361991 is a wasteful number, since it uses less digits than its factorization.

65361991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3844840.

The product of its digits is 43740, while the sum is 40.

The square root of 65361991 is about 8084.6763076823. The cubic root of 65361991 is about 402.8175876490.

The spelling of 65361991 in words is "sixty-five million, three hundred sixty-one thousand, nine hundred ninety-one".