65553821 has 2 divisors, whose sum is σ = 65553822. Its totient is φ = 65553820.

The previous prime is 65553757. The next prime is 65553823. The reversal of 65553821 is 12835556.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64080025 + 1473796 = 8005^2 + 1214^2 .

It is a cyclic number.

It is not a de Polignac number, because 65553821 - 2⁶ = 65553757 is a prime.

It is a Sophie Germain prime.

Together with 65553823, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65553823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32776910 + 32776911.

It is an arithmetic number, because the mean of its divisors is an integer number (32776911).

Almost surely, 2^65553821 is an apocalyptic number.

It is an amenable number.

65553821 is a deficient number, since it is larger than the sum of its proper divisors (1).

65553821 is an equidigital number, since it uses as much as digits as its factorization.

65553821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36000, while the sum is 35.

The square root of 65553821 is about 8096.5314178357. The cubic root of 65553821 is about 403.2112773370.

The spelling of 65553821 in words is "sixty-five million, five hundred fifty-three thousand, eight hundred twenty-one".