65090821 has 4 divisors (see below), whose sum is σ = 66678444. Its totient is φ = 63503200.

The previous prime is 65090791. The next prime is 65090833. The reversal of 65090821 is 12809056.

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 37149025 + 27941796 = 6095^2 + 5286^2 .

It is a cyclic number.

It is not a de Polignac number, because 65090821 - 2⁷ = 65090693 is a prime.

It is a super-3 number, since 3×65090821³ (a number of 24 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65090021) 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, 793750 + ... + 793831.

It is an arithmetic number, because the mean of its divisors is an integer number (16669611).

Almost surely, 2^65090821 is an apocalyptic number.

It is an amenable number.

65090821 is a deficient number, since it is larger than the sum of its proper divisors (1587623).

65090821 is a wasteful number, since it uses less digits than its factorization.

65090821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1587622.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 65090821 is about 8067.8882614969. Note that the first 3 decimals coincide. The cubic root of 65090821 is about 402.2597534949.

Adding to 65090821 its reverse (12809056), we get a palindrome (77899877).

The spelling of 65090821 in words is "sixty-five million, ninety thousand, eight hundred twenty-one".