65449991 has 4 divisors (see below), whose sum is σ = 66842592. Its totient is φ = 64057392.

The previous prime is 65449987. The next prime is 65449997. The reversal of 65449991 is 19994456.

65449991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 65449991 - 2² = 65449987 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (47), and also a Moran number because the ratio is a prime number: 1392553 = 65449991 / (6 + 5 + 4 + 4 + 9 + 9 + 9 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65449997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 696230 + ... + 696323.

It is an arithmetic number, because the mean of its divisors is an integer number (16710648).

Almost surely, 2^65449991 is an apocalyptic number.

65449991 is a deficient number, since it is larger than the sum of its proper divisors (1392601).

65449991 is a wasteful number, since it uses less digits than its factorization.

65449991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1392600.

The product of its digits is 349920, while the sum is 47.

The square root of 65449991 is about 8090.1168718381. The cubic root of 65449991 is about 402.9982841600.

The spelling of 65449991 in words is "sixty-five million, four hundred forty-nine thousand, nine hundred ninety-one".