642681840 has 80 divisors (see below), whose sum is σ = 2097187200. Its totient is φ = 162360576.

The previous prime is 642681839. The next prime is 642681841. The reversal of 642681840 is 48186246.

642681840 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (642681839) and next prime (642681841).

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642681841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65910 + ... + 75029.

It is an arithmetic number, because the mean of its divisors is an integer number (26214840).

Almost surely, 2^642681840 is an apocalyptic number.

642681840 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

642681840 is an abundant number, since it is smaller than the sum of its proper divisors (1454505360).

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

642681840 is a wasteful number, since it uses less digits than its factorization.

642681840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140974 (or 140968 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 39.

The square root of 642681840 is about 25351.1703871833. The cubic root of 642681840 is about 862.9759171405.

The spelling of 642681840 in words is "six hundred forty-two million, six hundred eighty-one thousand, eight hundred forty".