643156762609 has 2 divisors, whose sum is σ = 643156762610. Its totient is φ = 643156762608.

The previous prime is 643156762583. The next prime is 643156762627. The reversal of 643156762609 is 906267651346.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 641005194384 + 2151568225 = 800628^2 + 46385^2 .

It is a cyclic number.

It is not a de Polignac number, because 643156762609 - 2¹³ = 643156754417 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 643156762609.

It is not a weakly prime, because it can be changed into another prime (643156762679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321578381304 + 321578381305.

It is an arithmetic number, because the mean of its divisors is an integer number (321578381305).

Almost surely, 2^643156762609 is an apocalyptic number.

It is an amenable number.

643156762609 is a deficient number, since it is larger than the sum of its proper divisors (1).

643156762609 is an equidigital number, since it uses as much as digits as its factorization.

643156762609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9797760, while the sum is 55.

The spelling of 643156762609 in words is "six hundred forty-three billion, one hundred fifty-six million, seven hundred sixty-two thousand, six hundred nine".