642763949 has 2 divisors, whose sum is σ = 642763950. Its totient is φ = 642763948.

The previous prime is 642763943. The next prime is 642763969. The reversal of 642763949 is 949367246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 542563849 + 100200100 = 23293^2 + 10010^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642763949 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 642763897 and 642763906.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642763943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321381974 + 321381975.

It is an arithmetic number, because the mean of its divisors is an integer number (321381975).

Almost surely, 2^642763949 is an apocalyptic number.

It is an amenable number.

642763949 is a deficient number, since it is larger than the sum of its proper divisors (1).

642763949 is an equidigital number, since it uses as much as digits as its factorization.

642763949 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1959552, while the sum is 50.

The square root of 642763949 is about 25352.7897675976. The cubic root of 642763949 is about 863.0126668290.

The spelling of 642763949 in words is "six hundred forty-two million, seven hundred sixty-three thousand, nine hundred forty-nine".