642433409 has 2 divisors, whose sum is σ = 642433410. Its totient is φ = 642433408.

The previous prime is 642433403. The next prime is 642433471. The reversal of 642433409 is 904334246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 375274384 + 267159025 = 19372^2 + 16345^2 .

It is a cyclic number.

It is not a de Polignac number, because 642433409 - 2⁸ = 642433153 is a prime.

It is a super-2 number, since 2×642433409² = 825441369998722562, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (642433403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321216704 + 321216705.

It is an arithmetic number, because the mean of its divisors is an integer number (321216705).

Almost surely, 2^642433409 is an apocalyptic number.

It is an amenable number.

642433409 is a deficient number, since it is larger than the sum of its proper divisors (1).

642433409 is an equidigital number, since it uses as much as digits as its factorization.

642433409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 35.

The square root of 642433409 is about 25346.2701200788. The cubic root of 642433409 is about 862.8647073178.

The spelling of 642433409 in words is "six hundred forty-two million, four hundred thirty-three thousand, four hundred nine".