642928440 has 256 divisors, whose sum is σ = 2546795520. Its totient is φ = 125706240.

The previous prime is 642928409. The next prime is 642928477. The reversal of 642928440 is 44829246.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 155034 + ... + 159126.

It is an arithmetic number, because the mean of its divisors is an integer number (9948420).

Almost surely, 2^642928440 is an apocalyptic number.

642928440 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642928440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1273397760).

642928440 is an abundant number, since it is smaller than the sum of its proper divisors (1903867080).

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

642928440 is a wasteful number, since it uses less digits than its factorization.

642928440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4142 (or 4138 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 39.

The square root of 642928440 is about 25356.0336014922. The cubic root of 642928440 is about 863.0862789790.

The spelling of 642928440 in words is "six hundred forty-two million, nine hundred twenty-eight thousand, four hundred forty".