65811121 has 4 divisors (see below), whose sum is σ = 68080500. Its totient is φ = 63541744.

The previous prime is 65811089. The next prime is 65811127. The reversal of 65811121 is 12111856.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 21986721 + 43824400 = 4689^2 + 6620^2 .

It is a cyclic number.

It is not a de Polignac number, because 65811121 - 2⁵ = 65811089 is a prime.

It is a super-2 number, since 2×65811121² = 8662207294553282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (65811127) 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, 1134646 + ... + 1134703.

It is an arithmetic number, because the mean of its divisors is an integer number (17020125).

Almost surely, 2^65811121 is an apocalyptic number.

It is an amenable number.

65811121 is a deficient number, since it is larger than the sum of its proper divisors (2269379).

65811121 is a wasteful number, since it uses less digits than its factorization.

65811121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2269378.

The product of its digits is 480, while the sum is 25.

The square root of 65811121 is about 8112.4053769520. The cubic root of 65811121 is about 403.7381259628.

Adding to 65811121 its reverse (12111856), we get a palindrome (77922977).

The spelling of 65811121 in words is "sixty-five million, eight hundred eleven thousand, one hundred twenty-one".