642438864 has 200 divisors, whose sum is σ = 1944518400. Its totient is φ = 204602112.

The previous prime is 642438821. The next prime is 642438869. The reversal of 642438864 is 468834246.

It is a super-2 number, since 2×642438864² = 825455387955220992, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642438869) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3228237 + ... + 3228435.

It is an arithmetic number, because the mean of its divisors is an integer number (9722592).

Almost surely, 2^642438864 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 642438864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (972259200).

642438864 is an abundant number, since it is smaller than the sum of its proper divisors (1302079536).

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

642438864 is a wasteful number, since it uses less digits than its factorization.

642438864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319 (or 304 counting only the distinct ones).

The product of its digits is 884736, while the sum is 45.

The square root of 642438864 is about 25346.3777293719. The cubic root of 642438864 is about 862.8671495495.

The spelling of 642438864 in words is "six hundred forty-two million, four hundred thirty-eight thousand, eight hundred sixty-four".