643210685 has 16 divisors (see below), whose sum is σ = 837217920. Its totient is φ = 471562560.

The previous prime is 643210681. The next prime is 643210697. The reversal of 643210685 is 586012346.

It is not a de Polignac number, because 643210685 - 2² = 643210681 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643210681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26561 + ... + 44630.

It is an arithmetic number, because the mean of its divisors is an integer number (52326120).

Almost surely, 2^643210685 is an apocalyptic number.

643210685 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

643210685 is a deficient number, since it is larger than the sum of its proper divisors (194007235).

643210685 is a wasteful number, since it uses less digits than its factorization.

643210685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71348.

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 643210685 is about 25361.5986286354. The cubic root of 643210685 is about 863.2125585322.

The spelling of 643210685 in words is "six hundred forty-three million, two hundred ten thousand, six hundred eighty-five".