643280349 has 32 divisors (see below), whose sum is σ = 923120640. Its totient is φ = 397555200.

The previous prime is 643280329. The next prime is 643280369. The reversal of 643280349 is 943082346.

It is an interprime number because it is at equal distance from previous prime (643280329) and next prime (643280369).

It is not a de Polignac number, because 643280349 - 2⁵ = 643280317 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643280329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 368619 + ... + 370359.

It is an arithmetic number, because the mean of its divisors is an integer number (28847520).

Almost surely, 2^643280349 is an apocalyptic number.

It is an amenable number.

643280349 is a deficient number, since it is larger than the sum of its proper divisors (279840291).

643280349 is a wasteful number, since it uses less digits than its factorization.

643280349 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1941.

The product of its (nonzero) digits is 124416, while the sum is 39.

The square root of 643280349 is about 25362.9720064507. The cubic root of 643280349 is about 863.2437212965.

The spelling of 643280349 in words is "six hundred forty-three million, two hundred eighty thousand, three hundred forty-nine".