642071640 has 128 divisors (see below), whose sum is σ = 2330933760. Its totient is φ = 138123264.

The previous prime is 642071621. The next prime is 642071663. The reversal of 642071640 is 46170246.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 642071598 and 642071607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8202 + ... + 36761.

It is an arithmetic number, because the mean of its divisors is an integer number (18210420).

Almost surely, 2^642071640 is an apocalyptic number.

642071640 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 642071640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1165466880).

642071640 is an abundant number, since it is smaller than the sum of its proper divisors (1688862120).

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

642071640 is a wasteful number, since it uses less digits than its factorization.

642071640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45001 (or 44997 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 642071640 is about 25339.1325818387. The cubic root of 642071640 is about 862.7027105979.

The spelling of 642071640 in words is "six hundred forty-two million, seventy-one thousand, six hundred forty".