642491280 has 120 divisors (see below), whose sum is σ = 2162272320. Its totient is φ = 170968320.

The previous prime is 642491263. The next prime is 642491303. The reversal of 642491280 is 82194246.

642491280 is a `hidden beast` number, since 642 + 4 + 9 + 1 + 2 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (36).

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 23 ways as a sum of consecutive naturals, for example, 661195 + ... + 662165.

It is an arithmetic number, because the mean of its divisors is an integer number (18018936).

Almost surely, 2^642491280 is an apocalyptic number.

642491280 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 642491280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1081136160).

642491280 is an abundant number, since it is smaller than the sum of its proper divisors (1519781040).

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

642491280 is a wasteful number, since it uses less digits than its factorization.

642491280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1909 (or 1900 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 642491280 is about 25347.4117021837. The cubic root of 642491280 is about 862.8906157588.

The spelling of 642491280 in words is "six hundred forty-two million, four hundred ninety-one thousand, two hundred eighty".