643205341690 has 16 divisors (see below), whose sum is σ = 1157779889928. Its totient is φ = 257279853376.

The previous prime is 643205341687. The next prime is 643205341693. The reversal of 643205341690 is 96143502346.

It is an interprime number because it is at equal distance from previous prime (643205341687) and next prime (643205341693).

It can be written as a sum of positive squares in 4 ways, for example, as 235187171521 + 408018170169 = 484961^2 + 638763^2 .

It is a super-2 number, since 2×643205341690² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (643205341693) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1336764 + ... + 1753096.

Almost surely, 2^643205341690 is an apocalyptic number.

643205341690 is a deficient number, since it is larger than the sum of its proper divisors (514574548238).

643205341690 is a wasteful number, since it uses less digits than its factorization.

643205341690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570833.

The product of its (nonzero) digits is 466560, while the sum is 43.

The spelling of 643205341690 in words is "six hundred forty-three billion, two hundred five million, three hundred forty-one thousand, six hundred ninety".