642743729 has 2 divisors, whose sum is σ = 642743730. Its totient is φ = 642743728.

The previous prime is 642743711. The next prime is 642743743. The reversal of 642743729 is 927347246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 394618225 + 248125504 = 19865^2 + 15752^2 .

It is a cyclic number.

It is not a de Polignac number, because 642743729 - 2⁸ = 642743473 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 642743729.

It is not a weakly prime, because it can be changed into another prime (642743749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321371864 + 321371865.

It is an arithmetic number, because the mean of its divisors is an integer number (321371865).

Almost surely, 2^642743729 is an apocalyptic number.

It is an amenable number.

642743729 is a deficient number, since it is larger than the sum of its proper divisors (1).

642743729 is an equidigital number, since it uses as much as digits as its factorization.

642743729 is an evil number, because the sum of its binary digits is even.

The product of its digits is 508032, while the sum is 44.

The square root of 642743729 is about 25352.3909917783. The cubic root of 642743729 is about 863.0036172138.

The spelling of 642743729 in words is "six hundred forty-two million, seven hundred forty-three thousand, seven hundred twenty-nine".