642791688 has 192 divisors, whose sum is σ = 2044922880. Its totient is φ = 164799360.

The previous prime is 642791687. The next prime is 642791689. The reversal of 642791688 is 886197246.

It is an interprime number because it is at equal distance from previous prime (642791687) and next prime (642791689).

Its product of digits (1161216) is a multiple of the sum of its prime factors (448).

It is a self number, because there is not a number n which added to its sum of digits gives 642791688.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642791683) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2093631 + ... + 2093937.

It is an arithmetic number, because the mean of its divisors is an integer number (10650640).

Almost surely, 2^642791688 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 642791688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1022461440).

642791688 is an abundant number, since it is smaller than the sum of its proper divisors (1402131192).

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

642791688 is a wasteful number, since it uses less digits than its factorization.

642791688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448 (or 433 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 51.

The square root of 642791688 is about 25353.3368218071. The cubic root of 642791688 is about 863.0250813211.

The spelling of 642791688 in words is "six hundred forty-two million, seven hundred ninety-one thousand, six hundred eighty-eight".