642838643 has 4 divisors (see below), whose sum is σ = 654967728. Its totient is φ = 630709560.

The previous prime is 642838633. The next prime is 642838699. The reversal of 642838643 is 346838246.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 642838643 - 2⁶ = 642838579 is a prime.

It is a super-3 number, since 3×642838643³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 642838594 and 642838603.

It is not an unprimeable number, because it can be changed into a prime (642838613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6064463 + ... + 6064568.

It is an arithmetic number, because the mean of its divisors is an integer number (163741932).

Almost surely, 2^642838643 is an apocalyptic number.

642838643 is a deficient number, since it is larger than the sum of its proper divisors (12129085).

642838643 is a wasteful number, since it uses less digits than its factorization.

642838643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12129084.

The product of its digits is 663552, while the sum is 44.

The square root of 642838643 is about 25354.2628171280. The cubic root of 642838643 is about 863.0460950527.

The spelling of 642838643 in words is "six hundred forty-two million, eight hundred thirty-eight thousand, six hundred forty-three".