646220353 has 2 divisors, whose sum is σ = 646220354. Its totient is φ = 646220352.

The previous prime is 646220347. The next prime is 646220357. The reversal of 646220353 is 353022646.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 612661504 + 33558849 = 24752^2 + 5793^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-646220353 is a prime.

It is not a weakly prime, because it can be changed into another prime (646220357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323110176 + 323110177.

It is an arithmetic number, because the mean of its divisors is an integer number (323110177).

Almost surely, 2^646220353 is an apocalyptic number.

It is an amenable number.

646220353 is a deficient number, since it is larger than the sum of its proper divisors (1).

646220353 is an equidigital number, since it uses as much as digits as its factorization.

646220353 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 31.

The square root of 646220353 is about 25420.8645210976. The cubic root of 646220353 is about 864.5568260086.

Adding to 646220353 its reverse (353022646), we get a palindrome (999242999).

The spelling of 646220353 in words is "six hundred forty-six million, two hundred twenty thousand, three hundred fifty-three".