646490549 has 2 divisors, whose sum is σ = 646490550. Its totient is φ = 646490548.

The previous prime is 646490543. The next prime is 646490639. The reversal of 646490549 is 945094646.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 600495025 + 45995524 = 24505^2 + 6782^2 .

It is a cyclic number.

It is not a de Polignac number, because 646490549 - 2⁸ = 646490293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (646490543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323245274 + 323245275.

It is an arithmetic number, because the mean of its divisors is an integer number (323245275).

Almost surely, 2^646490549 is an apocalyptic number.

It is an amenable number.

646490549 is a deficient number, since it is larger than the sum of its proper divisors (1).

646490549 is an equidigital number, since it uses as much as digits as its factorization.

646490549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 933120, while the sum is 47.

The square root of 646490549 is about 25426.1784191018. The cubic root of 646490549 is about 864.6773046478.

The spelling of 646490549 in words is "six hundred forty-six million, four hundred ninety thousand, five hundred forty-nine".