65691811 has 4 divisors (see below), whose sum is σ = 65773624. Its totient is φ = 65610000.

The previous prime is 65691809. The next prime is 65691833. The reversal of 65691811 is 11819656.

65691811 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 4-Lehmer number, since φ(65691811) divides (65691811-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 65691811 - 2¹ = 65691809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65697811) 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, 39690 + ... + 41311.

It is an arithmetic number, because the mean of its divisors is an integer number (16443406).

Almost surely, 2^65691811 is an apocalyptic number.

65691811 is a deficient number, since it is larger than the sum of its proper divisors (81813).

65691811 is an equidigital number, since it uses as much as digits as its factorization.

65691811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81812.

The product of its digits is 12960, while the sum is 37.

The square root of 65691811 is about 8105.0484884422. The cubic root of 65691811 is about 403.4939973423.

It can be divided in two parts, 65691 and 811, that multiplied together give a square (53275401 = 7299²).

The spelling of 65691811 in words is "sixty-five million, six hundred ninety-one thousand, eight hundred eleven".