642854647 has 4 divisors (see below), whose sum is σ = 642929256. Its totient is φ = 642780040.

The previous prime is 642854603. The next prime is 642854651. The reversal of 642854647 is 746458246.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 746458246 = 2 ⋅373229123.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642854647 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 642854597 and 642854606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642852647) 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 in 3 ways as a sum of consecutive naturals, for example, 22393 + ... + 42274.

It is an arithmetic number, because the mean of its divisors is an integer number (160732314).

Almost surely, 2^642854647 is an apocalyptic number.

642854647 is a deficient number, since it is larger than the sum of its proper divisors (74609).

642854647 is an equidigital number, since it uses as much as digits as its factorization.

642854647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74608.

The product of its digits is 1290240, while the sum is 46.

The square root of 642854647 is about 25354.5784228411. The cubic root of 642854647 is about 863.0532570755.

It can be divided in two parts, 6428 and 54647, that added together give a triangular number (61075 = T₃₄₉).

The spelling of 642854647 in words is "six hundred forty-two million, eight hundred fifty-four thousand, six hundred forty-seven".