642739871 has 2 divisors, whose sum is σ = 642739872. Its totient is φ = 642739870.

The previous prime is 642739849. The next prime is 642739921. The reversal of 642739871 is 178937246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642739871 - 2¹⁰ = 642738847 is a prime.

It is a super-2 number, since 2×642739871² = 826229083546193282, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642739171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321369935 + 321369936.

It is an arithmetic number, because the mean of its divisors is an integer number (321369936).

Almost surely, 2^642739871 is an apocalyptic number.

642739871 is a deficient number, since it is larger than the sum of its proper divisors (1).

642739871 is an equidigital number, since it uses as much as digits as its factorization.

642739871 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 508032, while the sum is 47.

The square root of 642739871 is about 25352.3149041660. The cubic root of 642739871 is about 863.0018905149.

The spelling of 642739871 in words is "six hundred forty-two million, seven hundred thirty-nine thousand, eight hundred seventy-one".