642845844 has 72 divisors (see below), whose sum is σ = 1674003968. Its totient is φ = 207852480.

The previous prime is 642845839. The next prime is 642845849. The reversal of 642845844 is 448548246.

642845844 is a `hidden beast` number, since 64 + 2 + 8 + 4 + 584 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (642845839) and next prime (642845849).

It is a self number, because there is not a number n which added to its sum of digits gives 642845844.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642845849) 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 in 23 ways as a sum of consecutive naturals, for example, 648189 + ... + 649179.

Almost surely, 2^642845844 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642845844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (837001984).

642845844 is an abundant number, since it is smaller than the sum of its proper divisors (1031158124).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642845844 is a wasteful number, since it uses less digits than its factorization.

642845844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1525 (or 1520 counting only the distinct ones).

The product of its digits is 983040, while the sum is 45.

The square root of 642845844 is about 25354.4048244087. The cubic root of 642845844 is about 863.0493176197.

The spelling of 642845844 in words is "six hundred forty-two million, eight hundred forty-five thousand, eight hundred forty-four".