643606262197 has 2 divisors, whose sum is σ = 643606262198. Its totient is φ = 643606262196.

The previous prime is 643606262023. The next prime is 643606262237. The reversal of 643606262197 is 791262606346.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 628847414001 + 14758848196 = 792999^2 + 121486^2 .

It is a cyclic number.

It is not a de Polignac number, because 643606262197 - 2¹¹ = 643606260149 is a prime.

It is a super-2 number, since 2×643606262197² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (643606262297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321803131098 + 321803131099.

It is an arithmetic number, because the mean of its divisors is an integer number (321803131099).

Almost surely, 2^643606262197 is an apocalyptic number.

It is an amenable number.

643606262197 is a deficient number, since it is larger than the sum of its proper divisors (1).

643606262197 is an equidigital number, since it uses as much as digits as its factorization.

643606262197 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3919104, while the sum is 52.

The spelling of 643606262197 in words is "six hundred forty-three billion, six hundred six million, two hundred sixty-two thousand, one hundred ninety-seven".